bluuebunny/crossref_metadata_2025 huggingface dataset:
Anorexia/cachexia of chronic diseases: a role for the TGF‐β family cytokine MIC‐1/GDF15
Authors: Tsai Vicky W. W. , Husaini Yasmin , Manandhar Rakesh , Lee-Ng K. K. Michelle , Zhang Hong Ping , Harriott Kate , Jiang Lele , Lin Shu , Sainsbury Amanda , Brown David A. , Breit Samuel N.
Published: August 2012

Anorexia/cachexia is a common and currently mostly untreatable complication of advanced cancer. It is also a feature of a number of chronic diseases and can also occur as part of the normal ageing process. Over recent years, two different, but sometimes overlapping, processes have been identified to mediate anorexia/cachexia: those that act primarily on muscle reducing its mass and function, and processes that decrease nutrition leading to loss of both fat and muscle. In the case of at least some cancers, the latter process is sometimes driven by marked overexpression of macrophage inhibitory cytokine‐1/growth differentiation factor 15 (MIC‐1/GDF15). MIC‐1/GDF15 is a transforming growth factor beta (TGF‐β) family cytokine that is found in the serum of all normal individuals at an average concentration of about 0.6 ng/ml. Its increased expression in both cancers and other diseases can result in 10–100‐fold or more elevation of its serum levels. In experimental animals, serum MIC‐1/GDF15 levels at the lower end of this range induce anorexia by direct actions of the circulating cytokine on feeding centres in the brain. Mice with tumours overexpressing MIC‐1/GDF15 display decreased food intake, loss of lean and fat mass and cachexia. That this process also mediates anorexia/cachexia in humans is suggested by the fact that there is a direct correlation between the degree of serum MIC‐1/GDF15 elevation and the amount of cancer‐related weight loss, the first such relationship demonstrated. Further, in experimental animals, weight loss can be reversed by neutralisation of tumour‐produced MIC‐1/GDF15 with a specific monoclonal antibody, suggesting the possibility of effective therapy of patients with the devastating complication of anorexia/cachexia.
Strictly for Evangelical Parenting Support? The Case of Mothers of Preschoolers (MOPS)
Authors: Crowley Jocelyn Elise
Published: August 2012

Parenting poses a unique set of opportunities and challenges for both mothers who work for pay and for those who stay at home across the United States today. Specific types of “work-family” mothers’ groups have thus emerged as a way for these parents to provide support, information, and advocacy to one another in friendly communities. This study analyzes the boundary work undertaken by one national Christian mothers’ group, Mothers of Preschoolers (MOPS), to maximize its membership base and distinguish it from other work-family mothers’ organizations. In this article, I first probe how MOPS engages in a particular presentation of self that I call “open evangelism” to market its organization. Open evangelism combines both an open (nonreligious) and evangelical philosophy to appeal to a diversity of mothers across the country. I then use data collected from 25 in-depth interviews with MOPS members in 2009 in order to assess if and how this open evangelism is, in fact, experienced by members at the chapter level. I find that both open and evangelical themes emerge when members describe the benefits that they receive from joining the group and the challenges presented by parenthood, thereby suggesting that MOPS is successful in its self-presentation. I conclude with MOPS’ prospects for survival and growth in the competitive world of both religious and nonreligious mothers’ organizations.
Engineering NGF receptors to bind Grb2 directly uncovers differences in signaling ability between Grb2‐ and ShcA‐binding sites
Authors: Oku Shinichiro , van der Meulen Talitha , Copp Jeremy , Glenn Gary , van der Geer Peter
Published: August 2012

Grb2 and ShcA are two phosphotyrosine‐binding proteins that link receptor protein‐tyrosine kinases to activation of the Ras‐Erk pathway. While some receptors bind Grb2 directly, others bind ShcA, which provides a binding site for Grb2. In order to compare signal transduction through a Grb2‐binding site with signal transduction through a ShcA‐binding site, we replaced the ShcA‐binding site in the NGF receptor with a Grb2‐binding site. Our results show that the Grb2‐ and ShcA‐binding sites have similar abilities to activate the Ras‐Erk and PI 3‐kinase‐Akt pathways. In contrast, they displayed dramatic differences in their ability to activate DNA synthesis.
Construct Validity of a New Rating Scale for Self‐Reported Impairments in Persons With Late Effects of Polio
Authors: Brogårdh Christina , Lexell Jan , Lundgren‐Nilsson Åsa
Published: August 2012

Objective

To evaluate the construct validity of a new rating scale for self‐reported impairments in persons with late effects of polio.

Design

Psychometric analysis of data on self‐perceived impairments in persons with prior polio.

Participants

Two hundred seventy‐three persons with prior polio (119 men and 154 women; mean age, 63.5 years).

Method

Rasch analysis of a 13‐item rating scale with 5 response categories, in which the participants rated how much they have been bothered by various post‐polio–related impairments during the past 2 weeks.

Results

The initial analysis showed disordered categories, misfit with some of the items, multidimensionality, and local dependency. After adjustment of the categories, which resulted in a 4‐category rating scale, fit to the model was achieved, but the scale still showed signs of multidimensionality. Analyses of local dependency revealed correlations among some of the items, which resulted in a 5 testlet solution, which gave fit to the model and unidimensionality.

Conclusion

After adjustment of the categories and local dependency, this new rating scale, Self‐Reported Impairments in Persons With Late Effects of Polio, can be considered as unidimensional. The good psychometric properties implies that the Self‐Reported Impairments in Persons With Late Effects of Polio scale could be a useful rating scale that would increase our understanding of the impairments that persons with late effects of polio can experience. With further refinements, this scale may assist in the planning and evaluation of appropriate rehabilitation interventions.
Relationships of the Mediterranean dietary pattern with insulin resistance and diabetes incidence in the Multi-Ethnic Study of Atherosclerosis (MESA)
Authors: Abiemo Eunice E. , Alonso Alvaro , Nettleton Jennifer A. , Steffen Lyn M. , Bertoni Alain G. , Jain Aditya , Lutsey Pamela L.
Published: August 2012

Type 2 diabetes (T2D) is a highly prevalent but preventable disorder. We assessed the association between an a priori Mediterranean diet (MeDiet) score and fasting glucose and insulin at baseline and incident T2D after a 6-year follow-up in the Multi-Ethnic Study of Atherosclerosis. Dietary intake was measured at baseline using a 127-item FFQ in 5390 men and women aged 45–84 years free of prevalent diabetes and clinical CVD. A MeDiet score was created based on the intake of ten food components: vegetables; whole grains; nuts; legumes; fruits; ratio of monounsaturated:saturated fat; red and processed meat; dairy products; fish; alcohol. Multivariable linear and proportional hazards models were used to estimate the association of the MeDiet, categorised in quintiles, with baseline insulin and glucose, and incident diabetes, respectively. The models were adjusted for demographic, physiological and behavioural characteristics. After multivariable adjustment, individuals with a higher MeDiet score had lower baseline mean insulin levels (Q1: 5·8 (95 % CI 5·6, 6·0) μmol/l; Q5: 4·8 (95 % CI 4·6, 5·0) μmol/l; P for trend < 0·0001). A higher MeDiet score was also associated with significantly lower glucose levels after basic adjustment, but was attenuated after adjustment for waist circumference. During the follow-up, 412 incident diabetes events accrued. The MeDiet was not significantly related to the risk of incident diabetes (P for trend = 0·64). In summary, greater consistency with a Mediterranean-style diet, reflected by a higher a priori MeDiet score, was cross-sectionally associated with lower insulin levels among non-diabetics, and with lower blood glucose before adjustment for obesity, but not with a lower incidence of diabetes.
Minimal spectral functions of an ordinary differential operator
Authors: Mogilevskii Vadim
Published: August 2012

Letl[y]be a formally self-adjoint differential expression of an even order on the interval [0,b〉(b ≤ ∞) and letL0be the corresponding minimal operator. By using the concept of a decomposing boundary triplet, we consider the boundary problem formed by the equationl[y] − λy = f,f ∈ L2[0, b〉, and the Nevanlinna λ-dependent boundary conditions with constant values at the regular endpoint 0. For such a problem we introduce the concept of them-function, which in the case of self-adjoint separated boundary conditions coincides with the classical characteristic (Titchmarsh–Weyl) function. Our method allows one to describe all minimal spectral functions of the boundary problem, i.e. all spectral functions of the minimally possible dimension. We also improve (in the case of intermediate deficiency indicesn±(L0)and non-separated boundary conditions) the known estimate of the spectral multiplicity of the (exit space) self-adjoint extensionÃ ⊃ L0. Results are obtained for expressionsl[y]with operator-valued coefficients and arbitrary (equal or unequal) deficiency indicesn±(L0).
Singular solutions of a fully nonlinear 2 × 2 system of conservation laws
Authors: Kalisch Henrik , Mitrović Darko
Published: August 2012

Existence and admissibility of δ-shock solutions is discussed for the non-convex strictly hyperbolic system of equations

The system is fully nonlinear, i.e. it is nonlinear with respect to both unknowns, and it does not admit the classical Lax-admissible solution for certain Riemann problems. By introducing complex-valued corrections in the framework of the weak asymptotic method, we show that a compressive δ-shock solution resolves such Riemann problems. By letting the approximation parameter tend to zero, the corrections become real valued, and the solutions can be seen to fit into the framework of weak singular solutions defined by Danilov and Shelkovich. Indeed, in this context, we can show that every 2 × 2 system of conservation laws admits δ-shock solutions.
A higher category approach to twisted actions on c* -algebras
Authors: Buss Alcides , Meyer Ralf , Zhu Chenchang
Published: August 2012

C*-algebras form a 2-category with *-homomorphisms or correspondences as morphisms and unitary intertwiners as 2-morphisms. We use this structure to define weak actions of 2-categories, weakly equivariant maps between weak actions and modifications between weakly equivariant maps. In the group case, we identify the resulting notions with known ones, including Busby–Smith twisted actions and the equivalence of such actions, covariant representations and saturated Fell bundles. For 2-groups, weak actions combine twists in the sense of Green, and Busby and Smith.

The Packer–Raeburn Stabilization Trick implies that all Busby–Smith twisted group actions of locally compact groups are Morita equivalent to classical group actions. We generalize this to actions of strict 2-groupoids.
Commutative algebras in Drinfeld categories of abelian Lie algebras
Authors: Davydov Alexei , Futorny Vyacheslav
Published: August 2012

We describe (braided-) commutative algebras with non-degenerate multiplicative form in certain braided monoidal categories, corresponding to abelian metric Lie algebras (so-called Drinfeld categories). We also describe local modules over these algebras and classify commutative algebras with a finite number of simple local modules.
A review of the infectious agents, parasites, pathogens and commensals of European cockles (Cerastoderma eduleandC. glaucum)
Authors: Longshaw Matt , Malham Shelagh K.
Published: August 2012

A systematic review of the parasites, pathogens and commensals of the edible cockle (Cerastoderma edule) and of the lagoon cockle (Cerastoderma glaucum) has been completed. A total of 59 different conditions have been reported throughout the range of both of these hosts; of these 50 have been reported in edible cockles, and 28 in lagoon cockles. Cockles are hosts to viruses, bacteria, fungi (including Microsporidia), Apicomplexa, Amoeba, Ciliophora, Perkinsozoa, Haplosporidia, Cercozoa, Turbellaria, Digenea, Cestoda, Nematoda, Crustacea and Nemertea. A number of these have been reported sporadically although they may be associated with mortalities. In particular, mortalities have been associated predominately with digeneans and some protistan infections. In many cases pathology is marked in affected animals and parasites have been shown to reduce fecundity, alter burrowing behaviour and limit growth. This review provides information on the individual and population effects of these conditions as well as providing suggestions for future research. In particular, there has been a lack of taxonomic rigour applied to many studies and as a result there are a number of erroneous host records. There is a need to re-describe a number of parasite species and to determine the life cycle of those considered to be important mortality drivers.
Seasonal and starvation-induced changes on gonads and lipid reserves of the digestive gland of Nucella lapillus (Caenogastropoda)
Authors: Gonçalves Catarina Inês , Lobo-da-cunha Alexandre
Published: August 2012

This study was conceived to evaluate seasonal changes in the lipid reserves of the digestive gland of the carnivorous intertidal caenogastropod Nucella lapillus, using a stereological approach. Volume density of lipid droplets in the digestive gland, digestive gland weight and volume were assessed in animals collected in March, June, September and December on the Portuguese coast. Gonad development was evaluated to detect any relationship between lipid content in the digestive gland and the reproductive cycle. The quantitative light microscopic analysis demonstrates that lipid droplets are a major component of the digestive gland. In males, the digestive gland and its lipid reserves were quite stable without significant variations throughout the year. In females, the percentage of digestive gland volume occupied by lipid droplets was higher in June and December, coinciding with the highest values of digestive gland volume. Due to the conjugation of these two factors, in June and December the total amount of lipids in the digestive gland was substantially increased in females. In both males and females a relationship between the development status of the gonad and the lipid reserves of the digestive gland was not evident. However, significant differences in the digestive gland lipid reserves were detected between males and females in June and December, pointing to a sex related effect on lipid reserves. To evaluate the use of lipid reserves as energy source in N. lapillus, the consumption of digestive gland lipids was followed during a starvation experiment.
Reproductive biology of Trachurus mediterraneus (Carangidae): a detailed study for the Marmara–Black Sea stock
Authors: Demirel Nazli , Yüksek Ahsen
Published: August 2012

The reproductive biology of Mediterranean horse mackerel Trachurus mediterraneus was investigated in the Sea of Marmara over a one-year period. Duration and timing of the spawning season, gonad histology, oocyte development and size at sexual maturity were determined. The presence of all stages of oocytes without any distinct size hiatus indicated that oocyte development of Mediterranean horse mackerel is asynchronous with indeterminate fecundity. Spawning starts in May, peaks in July–August and ends in September. Sizes at 50% maturity were found to be 12.2 and 12.5 cm (total length) for females and males, respectively. Mean batch fecundity was calculated as 10136 ± 703 eggs. Our results on the size at sexual maturity and batch fecundity for the Sea of Marmara differed significantly from published results from the Mediterranean Sea. We ascribe these differences to different stock structures in these seas. Our results form the basis for future reproductive biology studies on the under-studied Marmara–Black Sea stock.
Shark scavenging and predation on cetaceans at Abrolhos Bank, eastern Brazil
Authors: Bornatowski Hugo , Wedekin Leonardo L. , Heithaus Michael R. , Marcondes Milton César C. , Rossi-Santos Marcos R.
Published: August 2012

Although it is largely assumed that shark predation and predation risk are unimportant to large cetaceans, whales can make up large portions of the diets of some shark species. We investigated interactions between sharks and cetaceans in the Abrolhos Bank (16°40′ to 19°40′S), off the eastern coast of Brazil, including scavenging and predation attempts on living humpback whales (Megaptera novaeangliae). In order to determine the frequency of shark bites on cetaceans, both living and postmortem, we used carcasses discovered along the coast of Abrolhos Bank between 2001 and 2010 and photographs of living cetaceans during systematic and opportunistic visual surveys from 2004 to 2009. We analysed a total of 221 cetacean carcasses, of which 150 (67.8%) were humpback whales. Large sharks had fed on 22.3% (35 of 150) of humpback whales carcasses, and 20.8% (10 of 48) of carcasses of other species. Only three living humpback whales (<1%) had bite scars from large sharks, suggesting that they at least occasionally target living humpbacks. Cookiecutter shark bite marks also were observed on both dead and living cetaceans, with numerous living humpbacks showing multiple bites. The abundance of humpback whale carcasses available over the Abrolhos Bank, mainly during the humpback breeding season, may be an important component of shark diets seasonally. Further work is needed to better understand the frequency of shark attacks on mysticetes, potential costs of sublethal injuries, and importance of whales to shark diets.
Thought disorder in mid-childhood as a predictor of adulthood diagnostic outcome: findings from the New York High-Risk Project
Authors: Gooding D. C. , Ott S. L. , Roberts S. A. , Erlenmeyer-Kimling L.
Published: August 2012

Background

Thought disorder has been proposed as an indicator of schizotypy, which is considered to be necessary but not sufficient for the development of schizophrenia. It is unclear whether thought disorder is an indicator of susceptibility (i.e. an endophenotype) for schizophrenia. The goal of the present study was to elucidate the role of thought disorder in relation to schizotypy by examining its presence in high-risk individuals during mid-childhood.

Method

The sample consisted of 265 subjects drawn from the New York High-Risk Project. Individuals at high risk for schizophrenia (i.e. offspring of parents with schizophrenia) were compared with individuals at low risk for schizophrenia (i.e. offspring of parents with affective disorder or offspring of psychiatrically normal parents). Videotaped interviews were rated for thought disorder using the Scale for the Assessment of Thought, Language, and Communication (TLC). The same subjects were administered diagnostic interviews in late adolescence/early adulthood.

Results

Although positive thought disorder was equally present in subjects with affective and non-affective psychoses, negative thought disorder (namely, poverty of speech and poverty of content of speech) was elevated only in subjects with schizophrenia-related psychosis. Logistic regression analyses revealed that negative thought disorder added to the prediction of schizophrenia-related psychosis outcomes over and above positive thought disorder.

Conclusions

These findings suggest that negative thought disorder may have a specific association with schizotypy, rather than a more general association with psychosis. The findings also support consideration of negative thought disorder as an endophenotypic indicator of a schizophrenia diathesis.
Prospective predictors of adolescent suicidality: 6-month post-hospitalization follow-up
Authors: Yen S. , Weinstock L. M. , Andover M. S. , Sheets E. S. , Selby E. A. , Spirito A.
Published: August 2012

Background

The aim of this study was to examine prospective predictors of suicide events, defined as suicide attempts or emergency interventions to reduce suicide risk, in 119 adolescents admitted to an in-patient psychiatric unit for suicidal behaviors and followed naturalistically for 6 months.

Method

Structured diagnostic interviews and self-report instruments were administered to adolescent participants and their parent(s) to assess demographic variables, history of suicidal behavior, psychiatric disorders, family environment and personality/temperament.

Results

Baseline variables that significantly predicted time to a suicide event during follow-up were Black race, high suicidal ideation in the past month, post-traumatic stress disorder (PTSD), childhood sexual abuse (CSA), borderline personality disorder (BPD), low scores on positive affectivity, and high scores on aggression. In a multivariate Cox regression analysis, only Black race, CSA, positive affect intensity and high aggression scores remained significant.

Conclusions

Our findings suggest the following for adolescent populations: (1) in a very high-risk population, risk factors for future attempts may be more difficult to ascertain and some established risk factors (e.g. past suicide attempt) may not distinguish as well; and (2) cross-cutting constructs (e.g. affective and behavioral dysregulation) that underlie multiple psychiatric disorders may be stronger predictors of recurrent suicide events than psychiatric diagnoses. Our finding with respect to positive affect intensity is novel and may have practical implications for the assessment and treatment of adolescent suicide attempters.
Structural Changes in Chinese Corruption
Authors: Ko Kilkon , Weng Cuifen
Published: August 2012

Given the rapid economic and administrative evolution that China has undergone during the last three decades, it is likely that corruption in China has been directly and indirectly affected by the changes that have taken place. However, the existing literature pays little attention to the impact of such changes on Chinese corruption, while emphasizing the seriousness of corruption. This article reviews how the major causes of Chinese corruption in the reform era have been alleviated in the 2000s. Some of the recent changes include the progress of the market economy, the advent of a merit-based civil service system, improvement of the budgeting and auditing system, fiscal recentralization and better monitoring of local governments' activities, and progress in anti-corruption regulation and enforcement. Consequently, we hypothesize that changes in the causes of corruption have led to structural changes in Chinese corruption. Our empirical analyses reveal that administrative reform has resulted in a decrease in the number of corruption cases related to the internal administrative process (embezzlement and misappropriation of public funds). At the same time, we also observe the aggravation of bribery. This suggests that Chinese corruption has made a transition from being an administrative issue to being a private–public transactional problem.
Generalised powerlocales via relation lifting
Authors: VENEMA YDE , VICKERS STEVE , VOSMAER JACOB
Published: August 2012

This paper introduces an endofunctor VT on the category of frames that is parametrised by an endofunctor T on the category Set that satisfies certain constraints. This generalises Johnstone's construction of the Vietoris powerlocale in the sense that his construction is obtained by taking for T the finite covariant power set functor. Our construction of the T-powerlocale VT out of a frame is based on ideas from coalgebraic logic and makes explicit the connection between the Vietoris construction and Moss's coalgebraic cover modality.

We show how to extend certain natural transformations between set functors to natural transformations between T-powerlocale functors. Finally, we prove that the operation VT preserves some properties of frames, such as regularity, zero-dimensionality and the combination of zero-dimensionality and compactness.
Challenges and successes of recruitment in the “angiotensin-converting enzyme inhibition in infants with single ventricle trial” of the Pediatric Heart Network
Authors: Pike Nancy A. , Pemberton Victoria , Allen Kerstin , Jacobs Jeffrey P. , Hsu Daphne T. , Lewis Alan B. , Ghanayem Nancy , Lambert Linda , Crawford Kari , Atz Teresa , Korsin Rosalind , Xu Mingfen , Ravishankar Chitra , Cnota James , Pearson Gail D.
Published: August 2012

Objectives

Identify trends of enrolment and key challenges when recruiting infants with complex cardiac diseases into a multi-centre, randomised, placebo-controlled drug trial and assess the impact of efforts to share successful strategies on enrolment of subjects.

Methods

Rates of screening, eligibility, consent, and randomisation were determined for three consecutive periods of time. Sites collectively addressed barriers to recruitment and shared successful strategies resulting in theInventory of Best Recruiting Practices. Study teams detailed institutional practices of recruitment in post-trial surveys that were compared with strategies of enrolment initially proposed in theInventory.

Results

The number of screened patients increased by 30% between the Initial Period and the Intermediate Period (p = 0.007), whereas eligibility decreased slightly by 7%. Of those eligible for entry into the study, the rate of consent increased by 42% (p = 0.025) and randomisation increased by 71% (p = 0.10). During the Final Period, after launch of a competing trial, fewer patients were screened (−14%, p = 0.06), consented (−19%, p = 0.12), and randomised (−34%, p = 0.012). Practices of recruitment in the post-trial survey closely mirrored those in theInventory.

Conclusions

Early identification and sharing of best strategies of recruitment among all recruiting sites can be effective in increasing recruitment of critically ill infants with congenital cardiac disease and possibly other populations. Strategies of recruitment should focus on those that build relationships with families and create partnerships with the medical providers who care for them. Competing studies pose challenges for enrolment in trials, but fostering trusting relationships with families can result in successful enrolment into multiple studies.
OPTIMAL MONETARY POLICY AND FIRM ENTRY
Authors: Lewis Vivien
Published: August 2012

This paper characterizes optimal monetary policy in an economy with endogenous firm entry, a cash-in-advance constraint, and preset wages. Firms must make profits to cover entry costs; thus the markup on goods prices is efficient. However, because leisure is not priced at a markup, the consumption–leisure trade-off is distorted. Consequently, the real wage, hours, and production are suboptimally low. Because of the labor requirement for entry, insufficient labor supply also implies that entry is too low. This paper shows that in the absence of fiscal instruments such as labor income subsidies, the optimal monetary policy achieves higher welfare under sticky wages than under flexible wages. The policy maker uses the money supply instrument to raise the real wage—the cost of leisure—above its flexible-wage level, in response to expansionary shocks to productivity and entry costs. This increases labor supply, expanding production and firm entry.
LOOSE COMMITMENT IN MEDIUM-SCALE MACROECONOMIC MODELS: THEORY AND APPLICATIONS
Authors: Debortoli Davide , Maih Junior , Nunes Ricardo
Published: August 2012

This paper proposes a method and a toolkit for solving optimal policy with imperfect commitment. As opposed to the existing literature, our method can be employed in the medium- and large-scale models typically used in monetary policy. We apply our method to the Smets and Wouters model [American Economic Review97(3), 586–606 (2007)], for which we show that imperfect commitment has relevant implications for interest rate setting, the sources of business cycle fluctuations, and welfare.
Spitzer observations of planetary nebulae
Authors: Chu You-Hua
Published: August 2012

The Spitzer Space Telescope has three science instruments (IRAC, MIPS, and IRS) that can take images at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm, spectra over 5–38 μm, and spectral energy distribution over 52–100 μm. The Spitzer archive contains targeted imaging observations for more than 100 PNe. Spitzer legacy surveys, particularly the GLIMPSE survey of the Galactic plane, contain additional serendipitous imaging observations of PNe. Spitzer imaging and spectroscopic observations of PNe allow us to investigate atomic/molecular line emission and dust continuum from the nebulae as well as circumstellar dust disks around the central stars. Highlights of Spitzer observations of PNe are reviewed in this paper.
The SPM kinematic catalogue of Galactic planetary nebulae
Authors: López Jose-Alberto , Richer Michael G. , García-Díaz Maria-Teresa , Clark David M. , Meaburn John , Riesgo Hortensia , Steffen Wolfgang , Lloyd Myfanwy
Published: August 2012

The San Pedro Mártir kinematic catalogue of galactic planetary nebulae provides spatially resolved, long-slit, Echelle spectra for about 600 planetary nebulae, representing 55 observing runs and about 4000 individual integrations to date in this first release. The project is ongoing and will continue adding spectra to the database. The data are presented wavelength calibrated and corrected for heliocentric motion. This is the most extensive and homogeneous single source of data concerning the internal kinematics of the ionized nebular material in planetary nebulae. The catalogue is available through the world wide web at http://kincatpn.astrosen.unam.mx and an article will a full description of the catalogue will soon appear in the RevMexAA.
Common envelope evolution
Authors: Izzard Robert G. , Hall Philip D. , Tauris Thomas M. , Tout Christopher A.
Published: August 2012

Many binary star systems are not wide enough to contain the progenitor stars from which they were made. One explanation for this is that when one star becomes a red giant a common envelope forms around both stars in the binary system. The core of the giant and its companion star continue to orbit one another inside the envelope. Frictional energy deposited into the common envelope may lead to its ejection and, if so, a close binary system is formed from the core of the former giant star and its relatively untouched companion. When the primary is an asymptotic giant branch star the core becomes a hot carbon-oxygen white dwarf which may ionise the ejected envelope and illuminate a planetary nebula. Many other types of binary systems form through common envelope evolution such as low-mass X-ray binaries and cataclysmic variables. In the case of a failed envelope ejection when the cores merge, rapidly-rotating solitary giants similar to FK Comae stars form. In this short review we focus on attempts to constrain parameters of common envelope evolution models and also describe the latest efforts to model this elusive phase of binary stellar evolution.
Magnetic towers and binary-formed disks: New results for planetary nebula evolution
Authors: Huarte-Espinosa Martín , Frank Adam
Published: August 2012

We present new results of 3-D AMR MHD simulations focusing on two distinct aspects of PPN evolution. We first report new simulations of collimated outflows driven entirely by magnetic fields. These Poynting flux dominated “magnetic towers” hold promise for explaining key properties of PPN flows. Our simulations address magnetic tower evolution and stability. We also present results of a campaign of simulations to explore the development of accretion disks formed via wind capture. Our result focus on the limits of disk formation and the range of disk properties.
Multipolar planetary nebulae: Not as geometrically diversified as thought
Authors: Chong Sze-Ning , Kwok Sun , Imai Hiroshi , Tafoya Daniel
Published: August 2012

We present a general three-dimensional model of multipolar planetary nebulae (PNe). By rotating to different viewing angles and adjusting the angles between the multiple lobes, we demonstrate that the model is able to reproduce HST Hα images of 20 multipolar young PNe. Though this model only considers the geometrical projection effects, it significantly unifies the selected PNe and can be considered as a first-order fundamental model of the “multipolar” morphological class. This kind of model reduces complexity and is essential to pursuing of the shaping mechanism. In addition, we illustrate that under some special conditions, i.e. in certain viewing angles, or with low sensitivity, it will be hard to imagine that the projected image originates from a multipolar-lobed model.
Jet power in pre-planetary nebulae: Observations vs. theory
Authors: Huggins Patrick J.
Published: August 2012

High velocity jets are among the most prominent features of a wide class of planetary nebulae, but their origins are not understood. Several different types of physical models have been suggested to power the jets, but there is no consensus or preferred scenario. We compare current theoretical ideas on jet formation with observations, using the best studied pre–planetary nebulae in millimeter CO, where the dynamical properties are best defined. In addition to the mass, velocity, momentum, and energy of the jets, the mass and energetics of the equatorial mass-loss that typically accompanies jet formation prove to be important diagnostics. Our integrated approach provides estimates for some key physical quantities – such as the binding energy of the envelope when the jets are launched – and allows testing of model features using correlations between parameters. Even with a relatively small sample of well-observed objects, we find that some specific scenarios for powering jets can be ruled out or rendered implausible, and others are promising at a quantitative level.
(F)UV spectral analysis of 15 extremely hot, hydrogen-rich central stars of planetary nebulae
Authors: Ziegler Marc , Rauch Thomas , Werner Klaus , Kruk Jeffrey W.
Published: August 2012

We present results of a (F)UV spectral analysis of 15 hot, hydrogen-rich central stars of planetary nebulae (CSPNe) of DAO-type (A 7, A 31, A 35, A 39, NGC 3587, NGC 6720, NGC 6853, NGC 7293, PuWe 1, Sh 2-174) and O(H)-type (A 36, Lo 1, LSS 1362, NGC 1360, NGC 4361). The sample covers a wide range of parameters (Teff ≈ 70–130 kK, log g = 5.4–7.4). It represents different stages of post-AGB evolution. The derived stellar parameters are crucial constraints for AGB nucleosynthesis and stellar evolutionary calculations. Detailed spectral analyses using fully line-blanketed NLTE model atmospheres including 23 elements from hydrogen to nickel are performed. Additional modeling of the ISM line absorption enables to unambigiously identify nearly all observed lines and to improve both, the photospheric as well as the ISM model.
Planetary nebulae in the Magellanic Clouds and Local Group galaxies
Authors: Reid Warren A.
Published: August 2012

The Magellanic Clouds are close enough to the Milky Way to provide an excellent environment in which to study extragalactic PNe. Most of these PNe are bright enough to be spectroscopically observed and spatially resolved. With the latest high resolution detectors on today's large telescopes it is even possible to directly observe a large number of central stars. Magellanic Cloud (MC) PNe provide several astrophysical benefits including low overall extinction and a good sample size covering a large range of dynamic evolutionary timescales while the known distances provide a direct estimation of luminosity and physical dimensions. Multi-wavelength surveys are revealing intriguing differences between MC and Galactic PNe.

Over the past 5 years there has been a substantial increase in the number of PNe discovered in the Large Magellanic Cloud (LMC) in particular. Deep surveys have allowed the faint end of the luminosity function to be investigated, finally providing a strong clue to its overall shape. In so doing, the surveys are approaching completeness, estimated at ~80% in the LMC (~120 deg2) and ~65% in the Small Magellanic Cloud (SMC) (~20 deg2).

The number of galaxies comprising the Local Group (LG) and its outskirts has been growing steadily over the past 5 years and now numbers 48. Most of the 7 newly discovered galaxies are dwarf spheroidal (dSph) in structure and range from 7.6 to 755 kpc from the Milky Way. Nonetheless, there are no published searches for PNe in any of these galaxies to date. Apart from the LMC and Milky Way, the number of PN discoveries has been very modest and only one additional LG galaxy has been surveyed for PNe over the past 5 years. This paper provides the number of Local Group PNe currently known and estimates each galaxy's total PN population.
Planetary nebula populations and kinematics
Authors: Richer Michael G.
Published: August 2012

The brightest planetary nebulae achieve similar maximum luminosities, have similar ratios of chemcial abundances, and apparently share similar kinematics in all galaxies. These similarities, however, are not necessarily expected theoretically and appear to hide important evolutionary differences. As predicted theoretically, metallicity appears to affect nebular kinematics, if subtly, and there is a clear variation with evolutionary stage. To the extent that it can be investigated, the internal kinematics for galactic and extragalactic planetary nebulae are similar. The extragalactic planetary nebulae for which kinematic data exist, though, probably pertain to a small range of progenitor masses, so there may still be much left to learn, particularly concerning the kinematics of planetary nebulae that descend from the more massive progenitors.
Extragalactic planetary nebulae: Tracers of the chemical evolution of nearby galaxies
Authors: Magrini Laura , Stanghellini Letizia , Gonçalves Denise R.
Published: August 2012

The study of the chemical composition of Planetary Nebulae in external galaxies is of paramount importance for the fields of stellar evolution and chemical enrichment history of galaxies. In recent years a number of spectroscopic studies with 6-8m-class telescopes have been devoted to this subject improving our knowledge of, among other, the time-evolution of the radial metallicity gradient in disk galaxies, the chemical evolution of dwarf galaxies, and stellar evolution at low metallicity.
NGC 5128 - a nearby laboratory for planetary nebulae in a giant early-type galaxy
Authors: Walsh Jeremy R. , Jacoby George H. , Kuntschner Harald , Peletier Reynier F. , Rejkuba Marina , Walton Nicholas A. , Woodley Kristin A.
Published: August 2012

NGC 5128 at 3.8 Mpc is the nearest large elliptical galaxy and is ideally suited to a detailed study of its planetary nebula population. Two spectroscopic programmes are summarised. More than 1200 PNe candidates are known from imaging campaigns in NGC 5128 and accurate radial velocities of 1070 have been measured with the VLT FLAMES/Giraffe spectrometer. From these data a variety of studies of the galaxy kinematics are enabled, such as search for PN sub-groups, representing the relics of accretion of small galaxies. Emission line spectra were observed with VLT FORS and the light element abundances determined for 40 PNe through photoionization modelling. A spread in O abundance of about 0.9 dex is found but no obvious radial gradient out to 19 kpc. Comparison of the O abundance from these PN with the metallicity for the stellar population in the neighbourhood of the PN will probe the star formation and enrichment history of the galaxy. Full results from this analysis will be presented in a forthcoming paper.
3-D modeling of the collimated outflows of M1-32 and M2-42
Authors: Akras Stavros , López Jose-Alberto , Steffen Wolfgang
Published: August 2012

We present high resolution long-slit spectra from the San Pedro Martir kinematic catalogue (López et al. 2012) of plantetary nebulae M1-32 and M2-42 and their modeled PV diagrams using the 3-D morpho-kinematic code SHAPE. We find high-speed collimated outflows, surrounded by a equatorial thick torus/ring. The same SHAPE model is able to fit both planetary nebulae assuming one cylindrical velocity field for the outflows and one Hubble-law for the torus/ring concluding that they may be akin objects which just appear at different projections.
Ultraviolet emission line imaging of planetary nebulae with GALEX
Authors: Bianchi Luciana , Manchado Arturo , Forster Karl
Published: August 2012

GALEX (the Galaxy Evolution Explorer) has provided far-UV(1344-1786Å) and near-UV(1771-2831Å) imaging of several Planetary Nebulae (e.g., Bianchi et al. 2008, Bianchi 2012), with flux limits ~27.5 mag/sq.arcsec for objects in the Medium-deph Imaging Survey (MIS). PNe images in the GALEX broad-band UV filters include flux from both nebular line and continuum emission. We use the GALEX grism observing mode to obtain slitless spectral imaging of a sample of PNe with diameters >1′, in the near-UV. We show the first data from this program. The grism produces 2D images of the prominent UV nebular emission lines, when such lines dominate the flux. Combined with monochromatic images of diagnostic lines in the optical domain, such data help detect and interpret ionization and shock fronts, especially in faint nebular regions.
A catalogue of integrated Hα fluxes for ~1100 Galactic planetary nebulae
Authors: Bojičić Ivan S. , Frew David J. , Parker Quentin A.
Published: August 2012

We present new determinations of integrated Hα flux for ~1100 Galactic planetary nebulae measured from the Southern H-Alpha Sky Survey Atlas (SHASSA) and its northern counterpart, the Virginia Tech Spectral-Line Survey (VTSS). This catalogue is the largest homogeneous database of its kind, tripling the number of currently available measurements.
Planetary nebulae and the chemical evolution of the galactic bulge: New abundances of older objects
Authors: Cavichia Oscar , Costa Roberto D. D. , Mollá Mercedes , Maciel Walter J.
Published: August 2012

In view of their nature, planetary nebulae have very short lifetimes, and the chemical abundances derived so far have a natural bias favoring younger objects. In this work, we report physical parameters and abundances for a sample of old PNe located in the galactic bulge, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman Spectrograph. The new data allow us to extend our database including older, weaker objects that are at the faint end of the planetary nebula luminosity function (PNLF). The results show that the abundances of our sample are lower than those from our previous work. Additionally, the average abundances of the galactic bulge do not follow the observed trend of the radial abundance gradient in the disk. These results are in agreement with a chemical evolution model for the Galaxy recently developed by our group.
Photoionization modeling of the Galactic planetary nebulae Abell 39 and NGC 7027
Authors: Danehkar Ashkbiz , Frew David J. , Parker Quentin A. , De Marco Orsola
Published: August 2012

We estimate distances to the spherical planetary nebula Abell 39 and the bipolar planetary nebula NGC 7027 by interpolating from a wide grid of photoionization models using the 3-D code, MOCASSIN. We find preliminary distances of 1.5 kpc and 0.9 kpc respectively, with uncertainties of about 30%.
C/O abundance ratios and dust features in galactic planetary nebulae
Authors: Delgado-Inglada Gloria , Rodríguez Mónica
Published: August 2012

The iron depletion factors found in Galactic planetary nebulae (PNe) span over two orders of magnitude, suggesting that there are differences in the grain formation and destruction processes from object to object. We explore here the relation between the iron depletions, the infrared dust features, and the C/O abundance ratios in a sample of Galactic PNe. We find that those objects with C/O<1 show a trend of increasing depletions for higher values of C/O, whereas PNe with C/O>1 break the trend and cover all the range of depletions. Most of the PNe with C/O<1 show silicate features, but several PNe with C-rich features have C/O<1, probably reflecting the uncertainties associated with the derivation of C/O. PAHs are distributed over the entire range of iron depletions and C/O values.
Kn 26: a textbook case hourglass planetary nebula with a twist
Authors: Guerrero Martín A. , Vázquez Roberto , Miranda Luis F. , Ramos-Larios Gerardo
Published: August 2012

Kn 26 is a recently identified planetary nebula (PN). To confirm its nature and study its spatio-kinematical structure, we have obtained high spatial-resolution optical and near-IR narrowband images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data confirm the PN nature of Kn 26 and reveal features typical of bipolar PNe: hourglass morphology, H2 emission, and nitrogen enrichment. A detailed analysis of its morphology and kinematics, however, suggests the presence of one additional pair of bipolar lobes that would make Kn 26 a new member of the class of quadrupolar PNe.
ATCA radio observations of compact planetary nabulae
Authors: Hajduk Marcin , Zijlstra Albert A.
Published: August 2012

We present new observations in the radio continuum of 31 planetary nebulae at 5 and 8 GHz with the Australian Telescope Compact Array. The observations are used to invesigate properties of the interstellar extinction toward Galactic Bulge.
GLMP 160 – the first [WR] star in a binary
Authors: Hajduk Marcin , van Hoof Peter A. M. , Zijlstra Albert A.
Published: August 2012

We discuss the results of the search for [WR] central stars in binary systems. GLMP 160 is the first [WR] central star in a binary system known. We analyze photometry, spectroscopy and imaging of this system.
Planetary nebula abundance determinations: A view from 1D-RHD simulations
Authors: Jacob Ralf , Sandin Christer , Schönberner Detlef , Steffen Matthias
Published: August 2012

In the last years (metallicity-dependent) radiation-hydrodynamics simulations have become a powerful tool to understand the formation and evolution of PNe in terms of simple morphologies and kinematics. Contrary to photoionization models, with their ad-hoc assumptions on structure and physics, the RHD models are self-consistent with respect to their density distribution, velocity field, chemical composition, and stellar evolution. We use our models as simple proxies for real PNe and investigate the reliability of common abundance determination methods, which are based on either plasma diagnostics or static photoionization (PI) models.
On the internal kinematics of PNe
Authors: Jacob Ralf , Schönberner Detlef , Lehmann Holger , Zwanzig Alena , Sandin Christer , Steffen Matthias
Published: August 2012

Our sample of round/elliptical double-shell PNe around central stars (CSs) with H-rich surface chemistry covers all evolutionary phases across the HRD. By means of high-resolution and high-S/N spectra we determine bulk matter velocities of the inner wind-driven rims and the maximum (= post-shock) gas velocities of the surrounding thermally expanding shells. Studying the details of the internal kinematics allows a look at processes of PN formation and at PN expansion history helping, for instance, to determine expansion distances.
New kinematic distance scale for the Galactic planetary nebulae
Authors: Kholtygin Alexander F. , Nikiforov Igor' I. , Akimkin Vitalii V.
Published: August 2012

We analyze the kinematics of disk planetary nebulae (PNe) to derive the formal Galactic center distance, R0, for three catalogues of PNe distances. Then we correct the catalogues' distance scales renormalizing the PNe distances by the ratios of formal R0 values to a best modern value of R0 =7.9 kpc. The created new catalogue of disk's PNe distances was found to be in a good agreement with distances by Stanghellini et al. (2008). Our catalogue of PNe distances was used to recalibrate the statistical distance scale for all Galactic PNe.