bluuebunny/crossref_metadata_2025 huggingface dataset:
Post‐kala‐azar dermal leishmaniasis mimicking leprosy relapse: a diagnostic dilemma
Authors: Arora Shikha , D'Souza Paschal , Haroon Mohammad A. , Ramesh V. , Kaur Onkar , Chandoke Raj Kumar
Published: December 2013

Objectives

Post‐kala‐azar dermal leishmaniasis (PKDL) is well recognized in the Indian subcontinent and is not infrequently confused with leprosy. The present report describes findings in an unusual case of PKDL.

Methods

We report an adult male who presented with firm nodules on the face and extremities, along with hypopigmented macules on the neck with deformity and hypoesthesia over the right upper extremity. The patient had experienced similar lesions seven years previously and had used multibacillary multi‐drug therapy for leprosy with complete resolution of the nodules.

Results

At the current presentation, skin smears from ear lobes and nodules were negative on Ziehl–Neelsen staining. Histopathological examination revealed a dermal lymphohistiocytic infiltrate with plasma cells. Giemsa staining of a tissue smear revealed Leishmania donovani bodies, and an rK39 antigen test was positive. The patient responded well to oral miltefosine.

Conclusions

This case is noteworthy because the patient exhibited an unusual combination of healed leprosy sequelae and active PKDL lesions, which caused a diagnostic dilemma.
Defect closure in the paranasal region: an enduring challenge
Authors: Riml Stefan , Larcher Lorenz , Grohmann Martin , Kompatscher Peter
Published: December 2013

Background

The paranasal region constitutes a demanding issue for the reconstructive surgeon. Its complex anatomy, with concavity in close contact with convexity, and a high density of functional and aesthetically important facial components demands specific concern. Due to such complexity, numerous procedures for the reconstruction of paranasal defects have been published, including skin grafts and flaps in random pattern or axial style from the glabella, upper lid, nasal root, or cheek.

Objectives

In this review, we recall classical reconstructive procedures and compare them with innovative procedures that could possibly gain importance in the following years.

Methods

We contrast the pros and cons concerning donor site morbidity, surgical elaborateness, and functional and aesthetic outcome, and substantiate our findings with photographic results from our own patient material.

Results and Conclusion

The reconstruction of paranasal defects remains a challenge; nevertheless, the growing toolbox of reconstructive instruments facilitates a perfect reconstructive result.
Quality of care factors associated with unplanned readmissions of older medical patients: a case–control study
Authors: Scott I. A. , Shohag H. , Ahmed M.
Published: December 2013

Background

Unplanned readmissions befall up to 25% of acutely hospitalised older patients, and many may be potentially preventable.

Aim

To assess the type and prevalence of quality of care factors associated with potentially preventable readmissions to a tertiary hospital general medicine service.

Methods

A retrospective case–control study was undertaken of hospital records of patients 65 years or older admitted acutely between 1 January 2005 and 31 December 2010. Readmissions up to 30 days postdischarge (cases) were purposively sampled according to frequencies of primary discharge diagnoses coded during the study period. Non‐readmitted patients (controls), matched according to age, sex and primary discharge diagnosis on index admission, were selected in a 1.7:1 ratio.

Results

One hundred and thirteen cases and 198 controls were analysed, the former demonstrating a significantly higher comorbidity burden (mean (±standard deviation) comorbidity score 6.6 (±2.2) vs 5.6 (±2.4), P = 0.003) and a higher proportion of individuals with one or more hospitalisations over the preceding 6 months (55.7% vs 8.1%, P < 0.001). Among readmitted patients, 50 (44.3%) were associated with one or more quality factors versus 23 (11.6%) controls (P < 0.001). The most common were: failure to develop/activate an advance care plan (18, 15.9% vs 2, 1.0%; P < 0.001); suboptimal management of presenting illness (13, 11.4% vs 0, 0%; P < 0.001); inadequate assessment of functional limitations (11, 9.7% vs 0, 0%; P < 0.001); and potentially preventable complication of therapy (8, 7.1% vs 1, 0.5%, P = 0.002).

Conclusions

Quality of care factors are more common among readmitted than among non‐readmitted older patients suggesting potential for remedial strategies. Such strategies may still have limited effects as older, frail patients with advanced diseases and multimorbidity will likely retain a high propensity for readmission despite optimal care.
Avocado/soybean unsaponifiables: a novel regulator of cutaneous wound healing, modelling and remodelling
Authors: Oryan Ahmad , Mohammadalipour Adel , Moshiri Ali , Tabandeh Mohammad R.
Published: December 2013

We investigated the effects of avocado/soybean unsaponifiables (ASU) on the healing response of cutaneous wound defect in rats. Sixty male rats were randomly divided into three groups including control, vehicle and treatment (n = 20 in each group). A 2 × 2 cm2 wound defect was made on the dorsum. The control, vehicle and treatment groups were treated daily with topical application of saline, cream and cream/ASU for 10 days, respectively. The wounds were monitored daily. The animals were euthanised at 10, 20 and 30 days post injury (D). The dry matter, hydroxyproline, collagen, n‐acetyl glucosamine (NAGLA) and n‐acetyl galactosamine (NAGAA) contents of the skin samples were measured and the histopathological and biomechanical characteristics of the samples were investigated. Statistics of P < 0·05 was considered significant. Treatment significantly increased tissue glycosaminoglycans and collagen contents at various stages of wound healing compared to controls. Treatment modulated inflammation, improved fibroplasia and produced high amounts of scar tissue at short term. At long term, treatment reduced the scar tissue size and increased the quality and rate of wound contraction and reepithelisation compared to controls. The treated lesions were more cosmetically pleasing and had significantly higher biomechanical characteristics than controls. ASU was effective in rat wound healing.
Use of fibrin monomer complex for screening for venous thromboembolism in the late pregnancy and post‐partum period
Authors: Kawamura Makoto , Fukuda Naoko , Suzuki Ayako , Kobayashi Yusuke , Matsuda Miho , Kanda Rieko , Kiseki Hisami , Tsukahara Yutaka , Hashimura Naohiko
Published: December 2013

Aim

We measured fibrin monomer complex (FMC) levels in all subjects who gave birth at our hospital and evaluated the feasibility of using FMC for screening for venous thromboembolism (VTE) in patients during late pregnancy and the post‐partum period.

Methods

From August 2010 to January 2012, all women who gave birth at our hospital were included. FMC and D‐dimer levels were determined during the late pregnancy and post‐partum periods. Compression ultrasonography of the lower extremities was performed in women with high FMC values.

Results

Of the 673 women enrolled, measurements were performed in 595 women (88.4%) during late pregnancy and in 610 women (90.6%) during the post‐partum period. The FMC levels were normal during late pregnancy in 400 women (67.2%) and during the post‐partum period in 399 women (78.5%) having vaginal delivery and 83 women (81.4%) who underwent a cesarean section. The FMC levels were abnormal during late pregnancy in 50 women (8.4%) and during the post‐partum period in nine women (1.8%) having vaginal delivery and in none (0%) who underwent a cesarean section. Ultrasonography detected thrombi in three (6.0%) women during late pregnancy. The FMC levels were strongly correlated with D‐dimer levels (R = 0.726, P < 0.0001, in late pregnancy; and R = 0.888, P < 0.0001, in the post‐partum period following vaginal delivery).

Conclusion

FMC levels could identify pregnancy‐related abnormalities requiring compression ultrasonography examination, without changing the cut‐off values for non‐pregnant individuals. Thus, this marker may be used to screen for VTE.
Effect of cytochrome P‐450 epoxygenase and hydroxylase metabolites on rat myometrium contractility in non‐pregnancy, late pregnancy and late pregnancy under inflammatory conditions
Authors: Corriveau Stéphanie , Berthiaume Maryse , Girard Isabelle , Nolin Marc‐Antoine , Rousseau Eric , Pasquier Jean‐Charles
Published: December 2013

Aim

The aim of the present experimental study was to assess the tocolytic effect of eicosanoids on myometrium from non‐pregnant and pregnant rats with or without an induced inflammatory condition.

Methods

Three hundred myometrial rings were obtained by median laparotomy from 50 Sprague–Dawley rats divided into three groups: (i) non‐pregnant (n = 15); (ii) pregnant in absence (n = 20); or (iii) pregnant in presence (n = 15) of lipopolysaccharide treatment, timed at 22 days of pregnancy. Spontaneous contractile activities were compared by isometric tension measurements. The effects of epoxy‐ and hydroxyeicosanoids derived from arachidonic acid as well as specific enzyme inhibitors were assessed. Changes were expressed as percentage of basal activity by calculating the area under the curve as a function of drug concentration and compared to the effect of the vehicle.

Results

A decrease in contractile activity ranging 10–25% was observed upon addition of epoxy‐ and hydroxyeicosanoids. Increasing epoxyeicosanoid bioavailability by inhibiting their degradation induced a tocolytic effect in the non‐pregnant group (20%) and in inflammation‐induced condition (40%). There was a significant difference in reactivity between groups and pregnancy condition. Semiquantification of metabolic enzymes that produce (cytochrome P‐450 epoxygenase) and degrade (soluble epoxide hydrolase) epoxyeicosanoids by western blot analysis revealed that these enzymes were mainly detected in the non‐pregnant group.

Conclusion

Eicosanoids can modify myometrial reactivity and their presence and effects are amplified in non‐pregnant and in inflammation‐induced condition. Our data suggest that in contrast to prostaglandins, epoxyeicosatrienoic acids are likely involved in the quiescence phase of parturition because they reduce the rhythmic contractile activity of uterine tissues in pregnant rats.
Prospective study of the MD‐twin score for antepartum evaluation of monochorionic diamniotic twins and its correlation with perinatal outcomes
Authors: Oohashi Masanao , Kaneko Masatoki , Sameshima Hiroshi , Kodama Yuki , Ikenoue Tsuyomu
Published: December 2013

Aim

To assess the outcome of monochorionic diamniotic (MD) twins with the aid of the MD‐twin score.

Methods

We enrolled 112 MD‐twin women in a tertiary perinatal center from 1997 to 2009. The MD‐twin score was prospectively applied once per week to women who did not have twin‐to‐twin transfusion syndrome (TTTS) after 26 weeks of gestation. The MD‐twin score consists of five variables: (i) fetal weight discordance; (ii) amniotic fluid discordance; (iii) hydrops fetalis; (iv) umbilical cord insertion; and (v) fetal heart rate monitoring. Normal was assigned a value of 0, abnormal was assigned 1, and total score was used for evaluation. Women with scores of 2 at 26 weeks gestation were managed expectantly until the score reached 3. Outcome measures were fetal death, neonatal death and neurological sequelae. The incidence of poor outcome according to score was investigated. The characteristics of MD twins with poor outcome were investigated.

Results

MD‐twin scores were applied to 90 women. Among them, 79 had scores of 2 or less and all had good outcomes. There were 11 women with a score of 3, four of whom had adverse outcome for at least one twin. Neonates born to women with scores of 0–2 had good outcomes without respect to birthweight percentile, while neonates with scores of 3 had poor outcomes when their birthweight percentile was less than the third percentile.

Conclusion

The MD‐twin score is applicable to 90% of MD twins without TTTS. An MD‐twin score of 2 is reassuring, while a score of 3 indicates increased risks for adverse outcome.
Association between oral DNA‐HPV and genital DNA‐HPV
Authors: Vidotti Lisandra Rocha , Vidal Flávia Castello Branco , Monteiro Sally Cristina Moutinho , Nunes Jomar Diogo , Salgado João Victor , Brito Luciane Maria Oliveira , Lopes Fernanda Ferreira
Published: December 2013

Background

Human papillomavirus (HPV) infection is one of the most common sexually transmitted diseases worldwide and is observed in both men and women. The presence of the virus is often associated with benign and malignant neoplasms of the oral cavity. We wished to investigate whether HPV infection in the genitalia was associated with HPV infection in the oral mucosa.

Methods

The prevalence of HPV in the oral cavity and genitalia was evaluated by DNA extraction from genital and oral cavity samples of 105 women, followed by nested PCR.

Results and Conclusions

The prevalence of HPV in the oral cavity was significantly higher in women who had genital HPV (P < 0.0001). Oral sex, alcohol, and tobacco consumption were not associated with the oral HPV infection.
Associations Among Text Messaging, Academic Performance, and Sexual Behaviors of Adolescents
Authors: Perry Raymond C.W. , Braun Rebecca , Cantu Michelle , Dudovitz Rebecca N. , Sheoran Bhupendra , Chung Paul J.
Published: December 2013

BACKGROUND

Text messaging is an increasingly common mode of communication, especially among adolescents, and frequency of texting may be a measure of one's sociability. This study examined how text messaging (“texting”) frequency and academic performance are associated with adolescent sexual behaviors.

METHODS

A cross‐sectional survey was administered to students at a public charter high school in Los Angeles County, CA. Two hundred fifty‐six high school students aged 14‐20 years participated. Outcome measures were history of vaginal sex, condom use, and worries about pregnancy. The main predictors were text messaging frequency and self‐reported academic performance.

RESULTS

In general, students with lower grades were more likely to have had vaginal sex. Greater texting frequency, however, was associated with vaginal sex only among students with higher grades. In addition, despite similar rates of condom use, sexually active students who both had good grades and texted frequently were more likely than others to have thought they or their partner might be pregnant.

CONCLUSIONS

The association between texting and sexual behaviors may vary based on adolescent's academic performance. Adolescent sexual health interventions may benefit from using a combination of sociability measures (such as texting frequency) and academic performance as risk predictors.
Relationship of Weight‐Based Teasing and Adolescents' Psychological Well‐Being and Physical Health
Authors: Greenleaf Christy , Petrie Trent A. , Martin Scott B.
Published: December 2013

BACKGROUND

To date, research has focused primarily on psychological correlates of weight‐based teasing. In this study, we extended previous work by also examining physical health‐related variables (eg, physical self‐concept and physical fitness [PF]).

METHODS

Participants included 1419 middle school students (637 boys and 782 girls). Of these, 245 (17.3%) reported being teased about being overweight. Participants completed measures of self‐esteem, depression, physical self‐concept, physical activity (PA) self‐efficacy, and self‐report physical and sedentary activities. Participants also completed PF testing.

RESULTS

After controlling for demographic characteristics, participants who were teased about being overweight had higher scores on depression and lower scores on self‐esteem, physical self‐concept, PA self‐efficacy, and health‐related measures of PF in comparison to participants who were not teased.

CONCLUSIONS

The results of this study support previous research indicating relationships between teasing and low levels of psychological well‐being, physical self‐concept, and PA self‐efficacy, and establishes one between weight‐based teasing and different types of PF. Research is needed to determine the potential causal nature of the relationships between teasing and fitness and evidence‐based interventions are needed to reduce weight‐based teasing and its potential effects on health and well‐being.
Public Bus Drivers and Social Inclusion: Evaluation of Their Knowledge and Attitudes Toward People With Intellectual Disabilities
Authors: Tillmann Vera , Haveman Meindert , Stöppler Reinhilde , Kvas Štefan , Monninger Daniel
Published: December 2013

Public bus drivers are a relevant part of the social network supporting people with intellectual disability (ID) in the independent use of public transport as their support can increase self‐determination and social inclusion. A study was undertaken that focused on (1) bus drivers' experiences with people with ID; (2) their knowledge about ID in general; and (3) their attitudes toward people with ID. Assessment of experiences, knowledge, and attitudes are important for the detection of potential psychological and social barriers for community inclusion. Experiences, knowledge, and attitudes were evaluated with a standardized questionnaire for a representative sample of 139 local bus drivers. The survey was conducted in a town in Germany with rural surroundings as part of the Nordhorn Public Transportation Intervention Study aiming to increase the independent use of public buses for people with ID. The authors found that some 19% of the bus drivers had experiences with people with ID in their private lives. Also, that knowledge about ID was rather moderate, differing widely according to specific items. Some drivers saw people with disabilities as passengers who are difficult and who needed more attention. Authors concluded that bus drivers are an essential part of the social support system of persons with ID and that assessment of bus drivers' attitudes, experiences, and knowledge is necessary to develop specific training programs. Valid information, communication, and social interaction skills training should be integrated in the regular training of bus drivers. Assessment and training of bus drivers could enhance the chances of persons with ID significantly to be mobile citizens in an inclusive society.
Forensic psychiatric experts under the legal microscope
Authors: Grønnerød Cato , Grøndahl Pål , Stridbeck Ulf
Published: December 2013

Purpose

We examined how 157 legal professionals view the role and performance of forensic psychiatric experts (psychiatrists and psychologists) in court, and what experiences they have with the experts.

Methods

The participants filled in an online survey with ratings and open‐ended questions.

Results

Their experience was fairly limited, but the general impression was one of overall satisfaction with the experts. Experience was not only valued but also clarity in language and presentation were important, together with verifiability and thoroughness. The ability or willingness to express doubt was also emphasized. In addition, a significant proportion felt they had observed differences between psychologists and psychiatrists, and they preferred psychiatrists based on a perception of higher professional skills.

Conclusions

Despite media uproars after controversial cases, the Norwegian system of court‐appointed experts received a positive review from the legal professionals; they report an overall positive experience with forensic psychiatric experts.
Asymptomatic bacteriuria is an independent predictor of urinary tract infections in an ambulatory cirrhotic population: a prospective evaluation
Authors: Ye Carrie , Kumar Deepali , Carbonneau Michelle , Keough Adam , Ma Mang , Tandon Puneeta
Published: December 2013

Background & Aims

Asymptomatic bacteriuria (ASB) is a risk factor for urinary tract infections (UTIs) in many patients without liver disease. It remains unclear whether a diagnosis of ASB in an outpatient with cirrhosis could be utilized to predict the subsequent development of a UTI. We undertook this study to determine the prevalence and incidence of ASB in an outpatient population and its association with UTI.

Methods

We prospectively evaluated 108 adult outpatients with cirrhosis over a 6‐month period. Monthly midstream urines (MSU) were performed to detect the occurrence of UTI and ASB (culture of ≥108 CFU/L of a urinary pathogen in the absence of UTI symptoms).

Results

Of 108 patients enrolled, 99 completed at least one MSU, for a total of 489 MSUs. Total follow‐up was 44 person‐years. The incidences of ASB and UTI were 181 and 250 per 1000 person‐years, respectively. The prevalences of ASB and UTI on the first MSU were 5 and 1%, respectively. In total, 8% of patients developed an episode of ASB and 11% developed a UTI during the study period. Univariate predictors of UTI were female gender, primary biliary cirrhosis, number of previous UTIs and preceding ASB. Preceding ASB was the only independent predictor of UTI on multivariate analysis, with an odds ratio of 6.2 (1.1–34.3), P = 0.04.

Conclusions

Cirrhotic patients have higher rates of ASB and UTI than reported in the general population. ASB is an independent predictor of UTI. Further studies are necessary to determine whether routine screening and antimicrobial treatment of ASB is warranted.
Characterizing the socially transmitted foraging tactic “sponging” by bottlenose dolphins (Tursiops sp.) in the western gulf of Shark Bay, Western Australia
Authors: Kopps Anna M. , Krützen Michael , Allen Simon J. , Bacher Kathrin , Sherwin William B.
Published: December 2013

Individual foraging tactics are widespread in animals and have ecological and evolutionary implications. Indo‐Pacific bottlenose dolphins (Tursiops sp.) in Shark Bay, Western Australia, exhibit a foraging tactic involving tool use, called “sponging.” Sponging is vertically, socially transmitted through the matriline and, to date, has been described in detail in the eastern gulf of Shark Bay (ESB). Here, we characterize sponging in the western gulf of Shark Bay (WSB), in which a different matriline engages in the behavior. We identified 40 individual “spongers” in 9 mo of boat‐based surveys over three field seasons. As is the case in ESB, the majority of WSB spongers was female and engaged in sponging in deep channel habitats. In contrast to ESB, however, there was no difference in the number of associates between spongers and nonspongers in WSB, and activity budgets differed between spongers and deep‐water nonspongers; spongers foraged more frequently and rested less than nonspongers. Group sizes in deep channel habitat, where sponging was prevalent, were typically larger than those in shallow habitat, except for foraging, perhaps indicative of higher predator abundance and/or scattered prey distribution in deep‐water habitat. This research improves our understanding of within‐population foraging variations in bottlenose dolphins.
Is there nursing phenomenology after Paley? Essay on rigorous reading
Authors: Petrovskaya Olga
Published: December 2013

At the bedside, nurses are expected to be precise when they read indications on screens and on the bodies of patients and decide on the meaning of words framed by the context of acute care. In academia, although there is no incident report to fill when we misread or misrepresent complex philosophical ideas, the consequences of inaccurate reading include misplaced epistemological claims and poor scholarship. A long and broad convention of nursing phenomenological research, in its various forms, claims a philosophical grounding in the ideas of Husserl, Heidegger, and other thinkers. But for nearly two decades, nurse phenomenologists' knowledge claims have been challenged by well‐informed criticisms, most notably by John Paley. At the heart of criticism lies an observation that Continental phenomenological thought is misrepresented in many nursing sources and that nursing phenomenology, both descriptive and interpretive, cannot appeal to the authority of either Husserl or Heidegger. Taking these criticisms seriously, I am asking, Is phenomenology after Paley possible? If misreading seems to be an issue, how can – or should – we read rigorously? My thinking through these questions is influenced by the ideas of Jacques Derrida. Under a condition of a play of language, of Derridian différance, when meaning is never self‐identical and never fully arrives, I suggest that one has to negotiate meanings through reading for differences. I develop this idea in relation to the methodological conventions of phenomenological nursing research and argue for a careful rereading of the whole field of phenomenological nursing research. Such rereading presupposes and necessitates interdisciplinary engagement between nursing and the humanities and interpretive social sciences. Greater familiarity with research practices of those disciplines that stress theoretical and writing rigour might make visible the limits of nursing research approaches and their quality criteria. An understanding of philosophical and theoretical works – a condition of quality scholarship – depends on our reading of both originary texts and contemporary literature from the humanities and the social sciences. This understanding, far from obliging researchers to always trace (often erroneously) their work to its philosophical roots, opens other, often more sound, methodological possibilities.
Stability of key micronutrients added to fortified maize flours and corn meal
Authors: Dunn Michael L. , Jain Vijaya , Klein Barbara P.
Published: December 2013

Maize is a dietary staple in many countries. Although nutritious in many ways and a good source of energy, typical maize lacks several key micronutrients (MNs) that are often added to maize meals or flours to enhance nutritional value. Many factors affect MN stability in maize products, including uncontrolled conditions during distribution, long storage times, and MN premix composition. Consumer preparation also affects the final MN content of food. This review summarizes research relating to MN stability during processing, transport, storage, and meal preparation, focusing on those MNs most often added to maize and maize‐based foods. Significant losses in B vitamins (B1, B2, B3, B6, B9, and B12) occur during manufacturing, distribution, and cooking. Added minerals (e.g., iron, zinc, calcium) are generally retained, although phytates in corn may affect bioavailability. Vitamins A and D3 are recent additions to fortification premixes for maize and are not well studied. Although there have been numerous studies of MN fortification in wheat flour, maize has not been as thoroughly examined, so recommendations are not as well supported. Future investigations should include well‐designed and executed studies of the most labile MNs added to maize flours and meals, and their fate during all steps of processing, shipping, and preparation.
Recording Complex Structures Using Close Range Photogrammetry: The Cathedral of Santiago De Compostela
Authors: Martínez Santiago , Ortiz Juan , Gil Ma Luz , Rego Ma Teresa
Published: December 2013

This paper describes the photogrammetric 3D modelling of complex buildings using low‐cost automatic image matching (AIM), consumer‐grade digital cameras and low‐altitude imagery. To verify the potential of this method, it was applied to the documentation of a specific case: the towers and roofs of the Cathedral of Santiago de Compostela in Spain, a UNESCO World Heritage Site. The design and development of a mechanism for coping with the elevation, based on telescopic masts, was essential. Models, orthophotos and plans have been obtained to determine and rigorously measure the geometry involved. Thereby it was possible to accurately record the materials and decorative elements based on the restitution of the granite stones. Furthermore, close range photogrammetry made the analysis and quantification of the inclination of the south tower possible.
Racial Norms: A Reinterpretation ofDuBois' “The Conservation of Races”
Authors: Gray David Miguel
Published: December 2013

Iargue that standard explanations ofDuBois' theory of race inappropriately characterize his view as attempting to provide descriptive criteria for races. Such an interpretation makes it both susceptible to Appiah's circularity objection and alienates it fromDuBois' central project of solidarity—which is the central point of “Conservation.”Ipropose that we should understand his theory as providing a normative account of race: an attempt to characterize what some races should be in terms of what other races are. In providing such an accountIwill also show how my interpretation ofDuBois' criteria avoids the circularity objection by making the criteria central to the project of solidarity. Thus, this interpretation avoids whatItake to be the two main problems with standard descriptive explanations ofDuBois' criteria.
Spatial Interdependence in US Outward FDI into Africa, Latin America and the Caribbean
Authors: Nwaogu Uwaoma G. , Ryan Michael
Published: December 2013

The existing literature on spatial interdependence in FDI flows has primarily focused on developed economies as hosts, with these hosts economically tied together via good infrastructure and historically strong/significant trade flows. In contrast, we explicitly test for the presence of spatial interdependence in developing hosts (Africa, Latin American and the Caribbean) where such ties are not as strong. For US outbound FDI between 1995 and 2007, our empirical results confirm third‐country effects do matter even when controlling for spatial and time‐period fixed effects. Based on the signs of the market potential and spatial lag coefficients, we find US FDI strategies into these regions as consistent with complex vertical specialisation.
The Trade Effects of US Anti‐dumping Actions against China Post‐WTO Entry
Authors: Shen Guobing , Fu Xiaolan
Published: December 2013

Since China's entry into the WTO, US anti‐dumping (AD) actions against China have increased, particularly with respect to multiple petitions. Distinguishing between US single and multiple petitions, we examine the trade effects of US AD actions against China based on an unbalanced panel of quarterly trade data. The results show that a US single petition investigation greatly restrains US imports of the filed products from China but also causes more significant import diversion from non‐named countries. In the short run, a preliminary AD duty imposed on China via a US multiple petition not only restrains US imports of the filed products from China but also prevents trade diversion from non‐named countries. In the long run, a final AD duty on China resulting from a US multiple petition creates a larger destructive effect on China and causes US import diversion from non‐named countries. Thus, a final AD duty imposed on China following a US multiple petition not only harms China's exports but also fails to help the US achieve import substitution. Furthermore, we have been able to reveal the negative trade effect of a preliminary AD duty even in cases where the ultimate decision is not to impose a final duty.
Retinal ganglion cell distribution and visual acuity in alpacas (Vicugna pacos)
Authors: Wang Hsiao‐Hui , Gallagher Shannon K. , Byers Stacey R. , Madl James E. , Gionfriddo Juliet R.
Published: December 2013

Objective

To investigate the distribution of retinal ganglion cells (RGCs) and visual acuity in alpacas (Vicugna pacos) through Brn‐3a immunofluorescent labeling.

Procedures

Five eyes from four healthy alpacas with normal ophthalmic examination findings were included in the study. The axial length of the globes was measured before fixation. All five retinas were treated with Brn‐3a antibodies to label RGCs. Images taken with a fluorescent microscope were used for RGC counting. RGC density maps were reconstructed by computer software. Visual acuity was estimated based on the results of peak RGC density and ocular anatomical parameters.

Results

The reconstructed retinal maps from Brn‐3a labeling showed a horizontal streak across the retinal meridian superior to the optic nerve head with a temporal, upward extension. The highest RGC densities were in the temporal retinas. The maximal visual acuity was located in the temporal retina and was estimated to range between 12.5 and 13.4 cycles per degree.

Conclusions

Alpacas have a horizontal streak across the retinal meridian superior to the optic disk with a temporal, upward extension based on the Brn‐3a labeling of RGCs. The maximal visual acuity was located in the temporal retina. The reconstructed retinal maps indicate the RGC topography of alpacas is similar to that of other herbivores, but is different from that of dromedary camels.
Upstream and Midstream Compression Applications: Part 2—Implications on Operation and Control of the Compression Equipment
Authors: Kurz Rainer , White Robert C. , Brun Klaus
Published: December 2013

Different upstream and midstream applications lead to different compression system characteristics and control requirements that are the result of compressor requirements (eg high pressure ratio, wide operating range) and the process requirements. Multiple unit installations, or installations with multiple compressors per train require specific process control considerations to match the compressors with the process system behavior and the objectives of the station or system operator. This paper explains the impact of the interaction between system characteristics and compressor characteristics, both under steady state and transient conditions. Also considered are concepts to optimize and control the units.
Identification of Eigenmodes and Determination of the Dynamical Behaviour of Open Impellers
Authors: Bidaut Yves , Baumann Urs
Published: December 2013

Whenever an open bladed impeller (without shroud) is implemented in a centrifugal compressor a key issue regarding the reliability of the compressor concerns the dynamical behaviour of this impeller. Due to the absence of the shroud this impeller can be operated at high tip speeds, hence allowing for higher volume flow. However the impeller reacts very sensitive to excitations leading to large blade vibrations with potential considerable dynamic stresses. In order to avoid resonance caused by fluctuating pressure distributions due to rotor-stator interactions special attention must be paid to the natural frequencies of the impeller which shall be determined with the highest accuracy possible.

Therefore this paper focuses on the identification of the natural frequencies of the impeller first. To validate the finite-element (FE) model extensive measurements of the natural frequencies are performed at standstill. Especially the set-up and results obtained with the Shaker-Laser vibrometer-tests are described in detail and compared to other measurement methods such as the Laser-Scaning-Vibrometry (LSV) and strain gauges.

Furthermore the prediction of the dynamic behaviour of the impeller is of considerable importance in the design of turbo compressors. For this purpose comprehensive measurements of the dynamic stress are carried out on the author’s company’s test rig. The paper describes the test arrangement including numerous strain gauges installed in different positions of the blades.

The last part of this paper describes a simplified approach for the evaluation of the dynamic stresses in the impeller blade. A substantial list of comprehensive lectures about coupled CFD–structural analysis to determine the dynamic behaviour of impeller blades is available. However, despite of considerable improvement in software and calculation methods in the last years, such analyses are still expensive and require very large capacities. The presented alternative calculation method is based on a harmonic analysis which is calibrated to the measurements and is the base for a further estimation of the life time of the impeller.
Effects of Bending Moments and Pre-Tightening Forces on the Flexural Stiffness of Contact Interfaces in Rod-Fastened Rotors
Authors: Gao Jin , Yuan Qi , Li Pu , Zhang Hongtao , Lv Zhiqiang
Published: December 2013

The rod-fastened rotor is comprised of a series of discs clamped together by a central tie rod or several tie rods on the pitch circle diameter. The equivalent flexural stiffness of contact interfaces in the rod-fastened rotor is the key concern for accurate rotor dynamic performance analysis. Each contact interface was modeled as a bending spring with stiffness of Kc and a hinge in this study. The contact states of the contact interfaces which depend on the pre-tightening forces and bending moments (static) have effects on Kc. The approach to calculating Kc in two contact states is presented. The first contact state is that the whole zone of the contact interface is in contact, Kc is determined by the contact layer which consists of asperities of the contact surfaces. Hertz contact theory and the GW (Greenwood and Williamson) statistical model are used to calculate the equivalent flexural stiffness of the contact layer Kcc. The second contact state is that some zones of the contact interface are separated (when the bending moment is relative large), the equivalent flexural stiffness of the rotor segment Ksf (not include Kcc) decreases as the material in the separated zone has no contribution to the bending load carrying capacity of the rotor. The strain energy which is calculated by the finite element method (FEM) is used to determine Ksf. The stiffness Ksf is equivalent to the series stiffness of the discs of the rotor segment with flexural stiffness of Kd and a spring with bending stiffness of Kcf in the location of the contact interface, so Kc is equal to the series stiffness of Kcc and Kcf in the second contact state. The results of a simplified rod-fastened rotor indicate that for a fixed pre-tightening force, Kcc decreases with bending moments in the first contact state whereas increases with bending moments in the second contact state. In addition, Kcf and Kc decreases abruptly with the increase of bending moments in the second contact state when the rotor is subjected to a relatively large pre-tightening force. Finally, the multipoint exciting method was used to measure the modal parameters of the experimental rod-fastened rotor. It is found that the experimental modal frequencies decrease as the pre-tightening force decreases.
Matching of Gas Turbines and Centrifugal Compressors: Oil and Gas Industry Practice
Authors: Taher Matt , Meher-Homji Cyrus
Published: December 2013

Gas turbine driven centrifugal compressors are widely used in the oil and gas industry. In evaluating the optimum selection of gas turbine drivers for centrifugal compressors, one of the main objectives should be to verify proper integration and matching of the centrifugal compressor to its gas turbine driver. Gas turbines are of standard designs, while centrifugal compressors are specifically designed to meet customer requirements. The purchaser should clearly specify process requirements and define possible operating scenarios for the entire life of the gas turbine driven centrifugal compressor train. Process requirements defined by the purchaser, will be used by the compressor designer to shape the aero-thermodynamic behavior of the compressor and characterize compressor performance. When designing a centrifugal compressor to be driven by a specific gas turbine, other design requirements are automatically introduced to centrifugal compressor design. Off-design performance, optimum power turbine speeds at site conditions as well as optimum power margin required for a future-oriented design must all be considered. Design and off-design performance of the selected gas turbine at site conditions influences the final selection of a properly matched centrifugal compressor design. In order to evaluate different designs and select the most technically viable solution, the purchaser should have a clear understanding of the factors influencing a proper match for a centrifugal compressor and its gas turbine driver. This paper discusses criteria for evaluating the most efficient combination of a centrifugal compressor and its gas turbine driver as an integral package from a purchaser’s viewpoint. It also addresses API standard requirements on gas turbine driven centrifugal compressors.
On the Identification of the Modal Parameters for a Flexible Turbomachinery Foundation
Authors: Yu Minli , Feng Ningsheng , Hahn Eric J.
Published: December 2013

The evaluation of the vibration behaviour of turbomachinery installations, where the model of the rotor support structure (foundation or casing) is unknown and the foundation has natural frequencies in or near the operating speed range, is still problematic. An attractive approach for identifying the foundation uses motion measurements of the rotor and the foundation at the bearing supports to indentify the parameters of an equivalent foundation, i.e. one which reproduces similar vibration responses over the operating speed range. Earlier work identified perfectly the modal parameters of a flexibly supported rigid foundation block, a situation involving only the six rigid body modes of the foundation, so that the equations of motion of the foundation could be written with a diagonal mass matrix. However, in practice, foundations such as gas turbine casings have flexural modes in or near the operating speed range, in which case it is unlikely that the foundation mass can be adequately represented by a diagonal mass matrix. Hence, this paper further develops the above identification technique to enable identification of a flexibly supported foundation block which has seven vibration modes in or near the operating speed range. It is shown by numerical experiments that the assumption of a diagonal mass matrix for the foundation does not result in a satisfactory equivalent foundation. On the other hand, when the identification procedure is enhanced to cater for a full symmetric foundation mass matrix, it is possible to identify the modal parameters of an equivalent foundation which, when substituted for the actual foundation of an unbalanced rotor bearing system, satisfactorily reproduces the system unbalance response. This is so even when the ‘measurement’ data used to identify the modal parameters is truncated to two digit accuracy to better represent practical measurement accuracy. It is concluded that the proposed foundation identification technique is likely to be applicable to practical field installations.
Numerical and Experimental Investigation of the Aerodynamic Excitation of a Model Low-Pressure Steam Turbine Stage Operating Under Low Volume Flow
Authors: Megerle Benjamin , Rice Timothy Stephen , McBean Ivan , Ott Peter
Published: December 2013

The diversification of power generation methods within existing power networks has increased the requirement for operational flexibility of plants employing steam turbines. This has led to the situation where steam turbines may operate at very low volume flow conditions for extended periods of time. Under operating conditions where the volume flow through the last stage moving blades (LSMBs) of a low-pressure (LP) steam turbine falls below a certain limit, energy is returned to the working fluid rather than being extracted. This so-called “ventilation” phenomenon produces non-synchronous aerodynamic excitation, which has the potential to lead to high dynamic blade loading. The aerodynamic excitation is often the result of a rotating phenomenon, with similarities to rotating stall, which is well known in compressors.

Detailed unsteady pressure measurements have been performed in a single stage model steam turbine operated with air under ventilation conditions. Detailed analysis revealed that the rotating excitation mechanism observed in operating steam turbines, is reproduced in the model turbine. 3D CFD has been applied to simulate the unsteady flow in the air model turbine. The numerical model consists of the single stage modeled as a full annulus, as well as the axial-radial diffuser. An unsteady CFD analysis has been performed for sufficient rotor revolutions such that the flow is globally periodic. It has been shown that the simulation reproduces well the characteristics of the phenomenon observed in the tests. The detailed insight into the flow field allows the drawing of conclusions as to the nature of the excitation mechanism. One result is that the LSMB tip clearance flow is found to have very little or no effect on the characteristics of mechanism for the case studied.
Thermo-Mechanical Fatigue Experiments of Single Crystal Hollow Turbine Blades
Authors: Jing Fulei , Wang Rongqiao , Hu Dianyin
Published: December 2013

The thermo-mechanical fatigue (TMF) experiments have been performed on the critical section of single crystal hollow turbine blades. An experimental system was constructed for the TMF experiments. A special loading device was designed and machined for the blades to provide loading conditions and simulate the stress distribution on the critical section. Induction heating and air cooling were utilized to provide anisothermal conditions. A new induction coil was designed to satisfy the requirements of the temperature distribution on the critical section. This TMF experimental system provided evidence that the loading and anisothermal conditions experienced by the turbine blades during service could be reproduced in a laboratory environment.
Rotordynamic Characteristics of a Flexure Pivot Pad Bearing With an Active and Locked Integral Squeeze Film Damper
Authors: Agnew Jeff , Childs Dara
Published: December 2013

Measured rotordynamic coefficients are presented for a flexure-pivot-pad journal bearing (FPJB) in a load-between-pad configuration with: (1) an active, and (2) locked integral squeeze film damper (ISFD). Prior rotordynamic-coefficient test results have been presented for FPJBs (alone), and rotor-response results have been presented for rotors supported by FPJBS with ISFDs; however, these are the first rotordynamic-coefficient test results for FPJBs with ISFDs.

A multi-frequency dynamic testing regime is employed. For both bearing configurations, quadratic curve fits provide good representation of the real portions of the dynamic-stiffness coefficients yielding a direct stiffness and a direct added-mass coefficient. The imaginary portions are well represented by linear curve fits, implying constant, frequency-independent direct-damping coefficients. Direct stiffness coefficients are ∼50% lower for the active-damper configuration, and direct damping coefficients are only modestly lower. The combination of ∼50% reduction in direct stiffness with a modest drop in direct damping indicates a very effective squeeze-film damper application.

Added-mass coefficients are normally lower for the active-damper configuration, and all coefficient trends (for changes in loading and shaft speed) are “flatter” for the active flexure pivot-pad damper bearing. The measured rotordynamic coefficients are used to calculate the whirl frequency ratio and indicate high stability for both bearing configurations.