bluuebunny/crossref_metadata_2025 huggingface dataset:
On the sum of the non-negative Lyapunov exponents for some cocycles related to the Anderson model
Authors: BINDER ILIA , GOLDSTEIN MICHAEL , VODA MIRCEA
Published: October 2015

We provide an explicit lower bound for the the sum of the non-negative Lyapunov exponents for some cocycles related to the Anderson model. In particular, for the Anderson model on a strip of width $W$, the lower bound is proportional to $W^{-\unicode[STIX]{x1D716}}$, for any $\unicode[STIX]{x1D716}>0$. This bound is consistent with the fact that the lowest non-negative Lyapunov exponent is conjectured to have a lower bound proportional to $W^{-1}$.
-algebras of labelled graphs III—-theory computations
Authors: BATES TERESA , CARLSEN TOKE MEIER , PASK DAVID
Published: October 2015

In this paper we give a formula for the$K$-theory of the$C^{\ast }$-algebra of a weakly left-resolving labelled space. This is done by realizing the$C^{\ast }$-algebra of a weakly left-resolving labelled space as the Cuntz–Pimsner algebra of a$C^{\ast }$-correspondence. As a corollary, we obtain a gauge-invariant uniqueness theorem for the$C^{\ast }$-algebra of any weakly left-resolving labelled space. In order to achieve this, we must modify the definition of the$C^{\ast }$-algebra of a weakly left-resolving labelled space. We also establish strong connections between the various classes of$C^{\ast }$-algebras that are associated with shift spaces and labelled graph algebras. Hence, by computing the$K$-theory of a labelled graph algebra, we are providing a common framework for computing the$K$-theory of graph algebras, ultragraph algebras, Exel–Laca algebras, Matsumoto algebras and the$C^{\ast }$-algebras of Carlsen. We provide an inductive limit approach for computing the$K$-groups of an important class of labelled graph algebras, and give examples.
Mixing in axisymmetric gravity currents
Authors: Samasiri Peeradon , Woods Andrew W.
Published: October 2015

We present new experiments to measure the rate of entrainment of ambient fluid into a high Reynolds number, axisymmetric, turbulent gravity current. The current is produced by the rapid release of a finite volume of aqueous salt solution from a lock of length $r_{o}$ into a diverging channel, $r>0$, of angle $9.5^{\circ }$, filled with a finite depth, $H$, of fresh water. Using light attenuation we measure the evolving density of the flow, and using dye studies we illustrate the process of mixing between the current and ambient fluid. After an initial adjustment, a circulation develops in the head of the flow: current fluid reaches the nose of the flow, rises up and moves backwards relative to the nose. We find that, owing to the mixing, the volume of the current increases as $V\sim 0.2r_{n}^{7/4}r_{o}^{1/4}H$ while the maximum depth of the head decreases as $h_{n}\sim 0.5H(r_{o}/r_{n})^{1/4}$, where $r_{n}$ is the location of the front of the current. Combining these results, we estimate that the recirculating current fluid mixes with a fraction $E=0.33\pm 0.09$ of the ambient fluid that is directly ahead of the current and displaced upwards by it. Some of the mixed fluid supplies the tail of the flow, while the remainder recirculates into the head, which becomes progressively more dilute. In accord with Huppert & Simpson (J. Fluid Mech., vol. 99, 1980, pp. 785–799), we find that the position of the front increases with time as $r_{n}\approx (1.28\pm 0.05)B^{1/4}t^{1/2}$, where $B$ is the total buoyancy of the flow. We also find that the maximum value of the vertical integral of the buoyancy $(\overline{g^{\prime }}h)_{n}$ decreases with the position of the nose according to the relation $(\overline{g^{\prime }}h)_{n}\approx (0.89\pm 0.12)Br_{n}^{-2}$, consistent with a Froude number $0.86\pm 0.07$. We compare our measurements with a new idealised self-similar solution of the depth-averaged equations that accounts for the mixing at the nose, the vertical shear in the velocity and the lateral stratification of the buoyancy within the current.
Association of food consumption with total volumes of visceral and subcutaneous abdominal adipose tissue in a Northern German population
Authors: Rüttgers Daniela , Fischer Karina , Koch Manja , Lieb Wolfgang , Müller Hans-Peter , Jacobs Gunnar , Kassubek Jan , Nöthlings Ute
Published: October 2015

Excess accumulation of visceral adipose tissue (VAT) is a known risk factor for cardiometabolic diseases; further, subcutaneous abdominal adipose tissue (SAAT) and the ratio of both (VAT:SAAT ratio) have been discussed as potentially detrimental. Information about the association between diet and adipose tissue is scarce. This study aimed to identify food group intake associated with VAT and SAAT and the VAT:SAAT ratio in a Northern German population. A cross-sectional analysis was conducted in 344 men and 241 women who underwent an MRI to quantify total volumes of VAT and SAAT. Intake of fourteen food groups was assessed with a self-administered 112-item FFQ. Linear regression models adjusted for age, sex, energy intake, physical activity, intake of other food groups and mutual adjustment for VAT and SAAT were calculated to analyse the associations between standardised food group intake and VAT and SAAT, or the VAT:SAAT ratio. Intakes of potatoes (P=0·043) and cakes (P=0·003) were positively and inversely, respectively, associated with both VAT and SAAT. By contrast, intake of cereals was negatively associated with VAT (P=0·045) only, whereas intakes of eggs (P=0·006) and non-alcoholic beverages (P=0·042) were positively associated with SAAT only. The association between eggs and non-alcoholic beverages with SAAT remained significant after further consideration of VAT. Intake of non-alcoholic beverages was also inversely associated with the VAT:SAAT ratio (P=0·001). Our analysis adds to the evidence that intake of foods is independently associated with VAT or SAAT volumes.
Estimation of daily dietary fluoride intake: 3-d food diaryv. 2-d duplicate plate
Authors: Omid N. , Maguire A. , O’Hare W. T. , Zohoori F. V.
Published: October 2015

The 3-d food diary method (3-d FD) or the 2-d duplicate plate (2-d DP) method have been used to measure dietary fluoride (F) intake by many studies. This study aimed to compare daily dietary F intake (DDFI) estimated by the 3-d FD and 2-d DP methods at group and individual levels. Dietary data for sixty-one healthy children aged 4–6 years were collected using 3-d FD and 2-d DP methods with a 1-week gap between each collection. Food diary data were analysed for F using the Weighed Intake Analysis Software Package, whereas duplicate diets were analysed by an acid diffusion method using an F ion-selective electrode. Pairedttest and linear regression were used to compare dietary data at the group and individual levels, respectively. At the group level, mean DDFI was 0·025 (sd0·016) and 0·028 (sd0·013) mg/kg body weight (bw) per d estimated by 3-d FD and 2-d DP, respectively. No statistically significant difference (P=0·10) was observed in estimated DDFI by each method at the group level. At an individual level, the agreement in estimating F intake (mg/kg bw per d) using the 3-d FD method compared with the 2-d DP method was within ±0·011 (95 % CI 0·009, 0·013) mg/kg bw per d. At the group level, DDFI data obtained by either the 2-d DP method or the 3-d FD method can be replaced. At an individual level, the typical error and the narrow margin between optimal and excessive F intake suggested that the DDFI data obtained by one method cannot replace the dietary data estimated from the other method.
ARISTOTLE'S COMPARATIVE LOGIC: A MODEST PROPOSAL
Authors: Gili Luca , Pezzini Giuseppe
Published: October 2015

Both W.D. Ross's and J. Brunschwig's editions of Aristotle's Topics contain the following passage:

ἔτι εἰ τοῦ αὐτοῦ τινος τὸ μὲν μᾶλλον τὸ δὲ ἧττον τοιοῦτο· καὶ εἰ τὸ μὲν τοιούτου μᾶλλον τοιοῦτο, τὸ δὲ μὴ τοιούτου, δῆλον ὅτι τὸ πϱῶτον μᾶλλον τοιοῦτο. (Γ 119 a20-2)

The passage is translated in the revised Oxford translation as follows: ‘Moreover, if in any character one thing exceeds and another falls short of the same standard; also, if the one exceeds something which possesses the character, while the other exceeds something which does not, then clearly the first thing exhibits that character in a greater degree’.
Permanent Crisis and Technosociality in Bruce Sterling's Distraction
Authors: CHERNIAVSKY EVA , FOSTER TOM
Published: October 2015

Bruce Sterling's science fiction novel Distraction (1999) envisions a near-future (mid-twenty-first-century) US in which the economy has collapsed, entire categories of skilled and professional labor have ceased to exist, rampant and endemic joblessness leaves masses of the unemployed to survive on the margins as squatters and scavengers, the infrastructure of entire regions is in ruins (Louisiana is described as “underwater” and the West as “on fire”), and the ongoing crisis has enabled the proliferation of ad hoc governance structures (“State-of-Emergency cliques”), even as democratic institutions survive (just barely) in the eviscerated form of pure spectacle. In this world, where, as one character puts it, “money just doesn't need human beings anymore,” a significant portion of the population have opted out of the money economy altogether. Appropriating biotech that can fabricate nutrition from scrub grass and weeds, the novel's nomad proles live off roadside detritus, which they also use to fabricate the phones and laptops central to their wired, moneyless reputation economy. This paper addresses the relation in the novel between economic crisis, the demise of representational politics (what Slavoj Žižek calls the “divorce” of “capitalism and democracy”), and alternative forms of sociality, particularly in the figure of the nomad proles, and of the urban squatters described as practicing a kind of “digital socialism” in what were once the public spaces of government (Senate office buildings, for example). If the reversion to nomadism most emphatically signposts the dissolution of the social body in Distraction, Sterling's representation of the nomad communities also insists that disaggregation is not the same thing as disorganization. Quite the contrary, as one character notes of the nomads, “organization is the only thing they've got.” We are interested in the ways in which this networked form of belonging both does and does not decode as ethnicity, as well as the ways in which it orients the proles both to structures of authoritarian governance and to the (equally wired) edifice of corporate capital. Along related lines, we ask what kind of resistance to capitalism is imagined in a “digital socialism” where private property and the private sphere are “turned inside out” through rfid (radio frequency identification) tagging and ubiquitous mutual “sousveillance”? To what extent do the disruptive effects of new technologies, as embodied by both the nomad proles and the socialist squatters, represent a genuine political opportunity, and to what extent do they represent a technologically determinist fantasy of capitalist collapse without class struggle, in the spaces of newly mediated social possibility created by permanent crisis?
Who Knows What's Going On? Mapping New Security Landscapes in Contemporary Espionage Fiction
Authors: PEPPER ANDREW
Published: October 2015

This article explores whether or to what extent the contemporary espionage novel is able to map and interrogate transformations in the post-9/11 security environment. It asks how well a form or genre of writing, typically handcuffed to the machinations and demands of the Cold War and state sovereignty, is able to adapt to a new security environment characterized by strategies of “risk assessment” and “resilience-building” and by modes or regimes of power not reducible to, or wholly controlled by, the state. In doing so, it thinks about the capacities of this type of fiction for “resisting” the formations of power it wants to make visible and is partly complicit with.
Keynes the Stock Market Investor: A Quantitative Analysis
Authors: Chambers David , Dimson Elroy , Foo Justin
Published: October 2015

The consensus view of the influential economist John Maynard Keynes is that he was a stellar investor. We provide an extensive quantitative appraisal of his performance over a quarter century and present detailed analysis of his archived trading records. His top-down approach initially generated disappointing returns with no evidence of any market-timing ability. However, from the early 1930s his performance improved as he evolved into a bottom-up stock picker with substantial active risk and pronounced size and value tilts. Our reconstruction of Keynes’s stock trading provides a unique record of realized performance and sheds light on how equity investing developed historically.
Effects of temperature and feeding regime on food consumption, growth, gonad production and quality of the sea urchin Strongylocentrotus intermedius
Authors: Zhao Chong , Feng Wenping , Wei Jing , Zhang Lisheng , Sun Ping , Chang Yaqing
Published: October 2015

Water temperature is one of the most important factors greatly affecting the aquaculture of sea urchins. However, no information is available on how to improve commercial traits of sea urchins reared at high water temperature. Here, we investigated the effects of water temperature and feeding regime on food consumption, growth, gonad production, gametogenesis and gonad quality of the sea urchin Strongylocentrotus intermedius. We found that high water temperature (22°C) significantly decreased dried food consumption and gonad production of S. intermedius, but not the somatic growth. The feeding regime of formulated feed and kelp has direct application potential in S. intermedius aquaculture, especially at field temperature. Feeding kelp alone is not effective in supporting growth and gonad production for S. intermedius cultured at high water temperature. This finding greatly challenges the current commonly used feeding regime (feeding macroalgae only) for S. intermedius cultured at high water temperature. Based on the current results, we suggest the feeding regimes of formulated feed and kelp or formulated feed alone for S. intermedius aquaculture at high water temperature. The present study provides new information for aquaculture of S. intermedius at high temperature and for production out of season.
Pulse Phase Estimation of X-ray Pulsar with the Aid of Vehicle Orbital Dynamics
Authors: Wang Yidi , Zheng Wei
Published: October 2015

A pulse phase estimation of an X-ray pulsar with the aid of vehicle orbital dynamics is proposed. The original continue-time X-ray pulsar signal model is modified to be a term of vehicle position and velocity varying with time, and a modified definition of pulse time of arrival is given. The modified signal model is further linearized around the predicted position and velocity of the vehicle to the second order. The initial phase and the coefficients of the extended signal model can be estimated by maximum likelihood estimator. Some simulations are performed to verify the method and show the method has robustness to the initial error within initial state of the vehicle and is capable of handling the phase-estimation problem for pulsars with low fluxes.
The impact of children's internalizing and externalizing problems on parenting: Transactional processes and reciprocal change over time
Authors: Serbin Lisa A. , Kingdon Danielle , Ruttle Paula L. , Stack Dale M.
Published: October 2015

Most theoretical models of developmental psychopathology involve a transactional, bidirectional relation between parenting and children's behavior problems. The present study utilized a cross-lagged panel, multiple interval design to model change in bidirectional relations between child and parent behavior across successive developmental periods. Two major categories of child behavior problems, internalizing and externalizing, and two aspects of parenting, positive (use of support and structure) and harsh discipline (use of physical punishment), were modeled across three time points spaced 3 years apart. Two successive developmental intervals, from approximately age 7.5 to 10.5 and from 10.5 to 13.5, were included. Mother–child dyads (N =138; 65 boys) from a lower income longitudinal sample of families participated, with standardized measures of mothers rating their own parenting behavior and teachers reporting on child's behavior. Results revealed different types of reciprocal relations between specific aspects of child and parent behavior, with internalizing problems predicting an increase in positive parenting over time, which subsequently led to a reduction in internalizing problems across the successive 3-year interval. In contrast, externalizing predicted reduced levels of positive parenting in a reciprocal sequence that extended across two successive intervals and predicted increased levels of externalizing over time. Implications for prevention and early intervention are discussed.
Adolescents’, mothers’, and fathers’ gendered coping strategies during conflict: Youth and parent influences on conflict resolution and psychopathology
Authors: Marceau Kristine , Zahn-Waxler Carolyn , Shirtcliff Elizabeth A. , Schreiber Jane E , Hastings Paul , Klimes-Dougan Bonnie
Published: October 2015

We observed gendered coping strategies and conflict resolution outcomes used by adolescents and parents during a conflict discussion task to evaluate associations with current and later adolescent psychopathology. We studied 137 middle- to upper-middle-class, predominantly Caucasian families of adolescents (aged 11–16 years, 65 males) who represented a range of psychological functioning, including normative, subclinical, and clinical levels of problems. Adolescent coping strategies played key roles both in the extent to which parent–adolescent dyads resolved conflict and in the trajectory of psychopathology symptom severity over a 2-year period. Gender-prototypic adaptive coping strategies were observed in parents but not youth, (i.e., more problem solving by fathers than mothers and more regulated emotion-focused coping by mothers than fathers). Youth–mother dyads more often achieved full resolution of conflict than youth–father dyads. There were generally not bidirectional effects among youth and parents’ coping across the discussion except boys’ initial use of angry/hostile coping predicted fathers’ angry/hostile coping. The child was more influential than the parent on conflict resolution. This extended to exacerbation/alleviation of psychopathology over 2 years: higher conflict resolution mediated the association of adolescents’ use of problem-focused coping with decreases in symptom severity over time. Lower conflict resolution mediated the association of adolescents’ use of angry/hostile emotion coping with increases in symptom severity over time. Implications of findings are considered within a broadened context of the nature of coping and conflict resolution in youth–parent interactions, as well as on how these processes impact youth well-being and dysfunction over time.
Stability and change in resolution of diagnosis among parents of children with autism spectrum disorder: Child and parental contributions
Authors: Yirmiya Nurit , Seidman Ifat , Koren-Karie Nina , Oppenheim David , Dolev Smadar
Published: October 2015

The contribution of change over time in parent and child characteristics to parents’ resolution of child's diagnosis was examined among 78 mothers and fathers of children with autism spectrum disorder. Children's characteristics (e.g., mental age and severity of symptoms), parental characteristics (e.g., attachment-related anxiety and stress level), and parents’ resolution of their child's diagnosis (resolved vs. unresolved) were examined at Time 1, and reassessed 3 years later at Time 2. Results indicated a deferential contribution of change in parent and child characteristics among mothers and fathers. An increase in child symptom severity and in maternal attachment-related anxiety, as well as longer durations of time since receiving the diagnosis, significantly predicted maternal resolved status at Time 2. Conversely, none of the changes in children's or paternal characteristics predicted paternal resolved status at Time 2. Results are discussed in relation to child and parental contributions to resolution, the differences in the adjustment and well-being of mothers and fathers of children with autism spectrum disorder, parental growth following receiving the diagnosis, and the need for intervention components specific to parental resolution and attachment-related anxiety.
Violent peer influence: The roles of self-esteem and psychopathic traits
Authors: Van Zalk Maarten Herman Walter , Van Zalk Nejra
Published: October 2015

Evidence for the risks of psychopathic personality traits for adolescent antisocial behavior are well documented in the literature. Little is known, however, about who the peers of adolescents with these traits are and to what extent they influence one another. In the current study, three dimensions of psychopathic traits were distinguished: grandiose–manipulative traits, callous–unemotional traits, and impulsive–irresponsible traits. A dynamic social network approach was used with three waves of longitudinal data from 1,772 adolescents (51.1% girls, M age = 13.03 at first measurement). Results showed that adolescents with grandiose–manipulative and callous–unemotional traits formed peer relationships with adolescents who had low self-esteem. Furthermore, peers' violence predicted stronger increases in violence for adolescents with low self-esteem than for other adolescents, and peers' violence predicted stronger increases in adolescent violence for peers with high psychopathic traits than for other peers. Thus, findings indicate that adolescents with low self-esteem are vulnerable to deviant peer influence from peers with psychopathic traits.
Child fear reactivity and sex as moderators of links between parenting and preschool behavior problems
Authors: Barnett Melissa A. , Scaramella Laura V.
Published: October 2015

Reduced supportive parenting and elevated negative parenting behaviors increase risks for maladaptive social adjustment during early childhood (e.g., Campbell, Shaw, & Gilliom, 2000). However, the magnitude of these risks may vary according to children's individual characteristics, such as sex and temperament. The current study examines whether children's sex and fear reactivity moderate the associations between mothers’ observed parenting and children's behavior problems 1 year later. The sample consists of 151 predominantly African American, low-income families with one sibling who is approximately 2 years old and the closest aged older sibling who is approximately 4 years old. Results from fixed-effects within-family models indicate that fear distress (i.e., fearfulness) moderated associations between mothers’ observed negative parenting and children's increased behavior problems, such that only those children with mean or higher observed fear distress scores showed increased behavior problems when exposed to mother's negative parenting. Child sex moderated associations between fear approach reactivity (i.e., fearlessness) and mothers’ observed supportive parenting. Specifically, low fear approach combined with supportive parenting was associated with fewer behavior problems for boys only. Implications of these findings for preventive intervention are discussed.
Food insecurity, overweight and obesity among low-income African-American families in Baltimore City: associations with food-related perceptions
Authors: Vedovato Gabriela M , Surkan Pamela J , Jones-Smith Jessica , Steeves Elizabeth Anderson , Han Eunkyung , Trude Angela CB , Kharmats Anna Y , Gittelsohn Joel
Published: October 2015

Objective

To examine associations between food insecurity, excess body weight, psychosocial factors and food behaviours among low-income African-American families.

Design

Cross-sectional survey of participants in the baseline evaluation of the B’More Healthy Communities for Kids (BHCK) obesity prevention trial. We collected data on socio-economic factors, food source destinations, acquiring food, preparation methods, psychosocial factors, beliefs and attitudes, participation in food assistance programmes, anthropometry and food security. We used principal component analysis to identify patterns of food source destinations and logistic regression to examine associations.

Setting

Fourteen low-income, predominantly African-American neighbourhoods in Baltimore City, MD, USA.

Subjects

Two hundred and ninety-eight adult caregiver–child (10–14 years old) dyads.

Results

Of households, 41·6 % had some level of food insecurity and 12·4 % experienced some level of hunger. Food-insecure participants with hunger were significantly more likely to be unemployed and to have lower incomes. We found high rates of excess body weight (overweight and obesity) among adults and children (82·8 % and 37·9 % among food insecure without hunger, 89·2 % and 45·9 % among food insecure with hunger, respectively), although there were no significant differences by food security status. Food source usage patterns, food acquisition, preparation, knowledge, self-efficacy and intentions did not differ by food security. Food security was associated with perceptions that healthy foods are affordable and convenient. Greater caregiver body satisfaction was associated with food insecurity and excess body weight.

Conclusions

In this setting, obesity and food insecurity are major problems. For many food-insecure families, perceptions of healthy foods may serve as additional barriers to their purchase and consumption.
Temperature Calibration forIn SituEnvironmental Transmission Electron Microscopy Experiments
Authors: Winterstein Jonathan P. , Lin Pin Ann , Sharma Renu
Published: October 2015

In situenvironmental transmission electron microscopy (ETEM) experiments require specimen heating holders to study material behavior in gaseous environments at elevated temperatures. In order to extract meaningful kinetic parameters, such as activation energies, it is essential to have a direct and accurate measurement of local sample temperature. This is particularly important if the sample temperature might fluctuate, for example when room temperature gases are introduced to the sample area. Using selected-area diffraction (SAD) in an ETEM, the lattice parameter of Ag nanoparticles was measured as a function of the temperature and pressure of hydrogen gas to provide a calibration of the local sample temperature. SAD permits measurement of temperature to an accuracy of ±30°C using Ag lattice expansion. Gas introduction can cause sample cooling of several hundred degrees celsius for gas pressures achievable in the ETEM.
Maternal pelvic size, fetal growth and risk of stroke in adult offspring in a large Swedish cohort
Authors: Heshmati A. , Chaparro M. P. , Koupil I.
Published: October 2015

Earlier research suggests that maternal pelvic size is associated with offspring’s stroke risk in later life. We followed 6362 men and women from Uppsala, Sweden, born between 1915 and 1929 from 1964 to 2008 to assess whether maternal pelvic size was associated with incidence of thrombotic stroke (TS), haemorrhagic stroke (HS) and other stroke (OS). Offspring whose mothers had a flat pelvis had lower birth weight and birth-weight-for-gestational-age compared with those who did not. Inverse linear associations of birth-weight-for-gestational-age were observed with TS and OS. Female offspring whose mothers had a flat pelvis had increased risk of TS, but flat pelvis was not associated with other types of stroke. A smaller difference between intercristal and interspinous diameters and a smaller external conjugate diameter were independently associated with HS, whereas no pelvic measurements were associated with OS. We conclude that a smaller pelvis in women may impact the health of their offspring in adulthood.
Moderating Role of Trait Hope in the Relation Between Painful and Provocative Events and Acquired Capability for Suicide
Authors: Mitchell Sean M. , Cukrowicz Kelly C. , Van Allen Jason , Seegan Paige L.
Published: October 2015

Abstract. Background: The interpersonal theory of suicide has gained empirical support as a conceptualization of suicide risk; however, little research has examined the role of individual traits, such as trait hope, within the interpersonal theory of suicide. Aims: The purpose of this study was to further investigate the role of trait hope components (i.e., pathways and agency) in acquired capability for suicide. Method: Participants were 711 college students who completed measures of acquired capability for suicide, painful and provocative events, and trait hope (i.e., pathways and agency). Linear regression was used to test the hypotheses. Results: As hypothesized, there was a positive relation between pathways and acquired capability. Contrary to our hypotheses, after controlling for gender there was a significant relation between agency and acquired capability. In addition, after controlling for gender, pathways did not moderate the relation between painful and provocative events and acquired capability, whereas agency did moderate this relation. Conclusion: Painful and provocative events should be assessed as a risk factor for acquired capability for suicide, and this may be more salient for individuals higher in the agency component of trait hope. Future research should consider examining the role of other traits within the interpersonal theory of suicide.
Trait Gratitude and Suicidal Ideation and Behavior
Authors: Krysinska Karolina , Lester David , Lyke Jennifer , Corveleyn Jozef
Published: October 2015

Abstract. Background: Despite the progress of positive psychology, current knowledge regarding suicide protective factors is limited. Trait gratitude (a tendency to experience gratitude in daily life) may protect against suicidal ideation and behavior. Aims: The study tested a model of causal effects among gratitude, religiosity, reasons for living, coping, and social support as predictors of suicidal ideation, suicide threats, and suicide attempts after controlling for depression and stressful life events. Method: A sample of 165 college students were administered measures of gratitude, religiosity, reasons for living, social support, coping skills, stress, and depression. The study assessed lifetime and current suicidal ideation as well as lifetime suicide threat and attempt. Results: Both gratitude and religiosity, along with social support, coping skills, and reasons for living, correlated negatively with prior suicidal ideation, but not with prior attempted suicide. After controlling for risk factor (depression and stress), the impact of gratitude and religiosity was no longer statistically significant. Conclusion: Further research could help understand the role of positive emotions and human strengths, such as gratitude, in preventing and alleviating suicidal ideation and behavior.
Meet the 2015–2016 Congressional Science Fellows
Authors: Evans Alison
Published: October 2015

A chemist versed in science communication and a geophysicist educated in business and law began yearlong stints on Capitol Hill serving as science advisers and learning firsthand how laws are made.
mTORC1 signaling is crucial for regulatory T cells to suppress macrophage‐mediated inflammatory response after acute myocardial infarction
Authors: Yang Keping , Zhang Yunfeng , Xu Chenhong , Li Xin , Li Dazhu
Published: October 2015

Post‐infarction inflammatory response results in worse remodeling and dysfunction following myocardial infarction (MI). Supression of post‐infarction inflammation would be a logical approach of alleviating post‐infarction injury and promoting cardiac repair. In this study, we investigated the significance of mTORC1 signaling in the anti‐inflammatory activity of regulatory T cells (Tregs) after MI. Using the murine MI model with wild type and Rag1−/− mice, we found that the mechanistic target of rapamycin compex 1 (mTORC1) signaling was upregulated in Tregs infiltrating into the infarcted myocardium, rather than in circulating Tregs after MI. The anti‐inflammatory activity of infiltrating Tregs was significantly stronger than that of circulating Tregs. This was demonstrated by a higher expression of anti‐inflammatory cytokines in the infiltrating Tregs and a robust suppression of proinflammatory cytokine production by macrophages. In an adoptive transfer analysis, compared with normal splenic Tregs, rapamycin‐treated splenic Tregs ineffectively suppressed the post‐infarction inflammatory response of infiltrating macrophages. In addition, in vitro cultured primary cardiomyocytes treated with mild oxygen glucose deprivation induced mTORC1 activation and a higher anti‐inflammatory activity of Tregs in a coculture assay. Our study identified a new mechanism by which infiltrating Tregs subdue post‐infarction inflammation. Understanding and utilizing this information would be helpful for designing new therapeutic interventions for MI.
Model of fibrolamellar hepatocellular carcinomas reveals striking enrichment in cancer stem cells
Authors: Oikawa Tsunekazu , Wauthier Eliane , Dinh Timothy A. , Selitsky Sara R. , Reyna-Neyra Andrea , Carpino Guido , Levine Ronald , Cardinale Vincenzo , Klimstra David , Gaudio Eugenio , Alvaro Domenico , Carrasco Nancy , Sethupathy Praveen , Reid Lola M.
Published: October 2015

The aetiology of human fibrolamellar hepatocellular carcinomas (hFL-HCCs), cancers occurring increasingly in children to young adults, is poorly understood. We present a transplantable tumour line, maintained in immune-compromised mice, and validate it as a bona fide model of hFL-HCCs by multiple methods. RNA-seq analysis confirms the presence of a fusion transcript (DNAJB1-PRKACA) characteristic of hFL-HCC tumours. The hFL-HCC tumour line is highly enriched for cancer stem cells as indicated by limited dilution tumourigenicity assays, spheroid formation and flow cytometry. Immunohistochemistry on the hFL-HCC model, with parallel studies on 27 primary hFL-HCC tumours, provides robust evidence for expression of endodermal stem cell traits. Transcriptomic analyses of the tumour line and of multiple, normal hepatic lineage stages reveal a gene signature for hFL-HCCs closely resembling that of biliary tree stem cells—newly discovered precursors for liver and pancreas. This model offers unprecedented opportunities to investigate mechanisms underlying hFL-HCCs pathogenesis and potential therapies.
Surprising trunk rotational capabilities in chimpanzees and implications for bipedal walking proficiency in early hominins
Authors: Thompson Nathan E. , Demes Brigitte , O’Neill Matthew C. , Holowka Nicholas B. , Larson Susan G.
Published: October 2015

Human walking entails coordinated out-of-phase axial rotations of the thorax and pelvis. A long-held assumption is that this ability relies on adaptations for trunk flexibility present in humans, but not in chimpanzees, other great apes, or australopithecines. Here we use three-dimensional kinematic analyses to show that, contrary to current thinking, chimpanzees walking bipedally rotate their lumbar and thoracic regions in a manner similar to humans. This occurs despite differences in the magnitude of trunk motion, and despite morphological differences in truncal ‘rigidity’ between species. These results suggest that, like humans and chimpanzees, early hominins walked with upper body rotations that countered pelvic rotation. We demonstrate that even if early hominins walked with pelvic rotations 50% larger than humans, they may have accrued the energetic and mechanical benefits of out-of-phase thoracic rotations. This would have allowed early hominins to reduce work and locomotor cost, improving walking efficiency early in hominin evolution.
Loss of KLF14 triggers centrosome amplification and tumorigenesis
Authors: Fan Guangjian , Sun Lianhui , Shan Peipei , Zhang Xianying , Huan Jinliang , Zhang Xiaohong , Li Dali , Wang Tingting , Wei Tingting , Zhang Xiaohong , Gu Xiaoyang , Yao Liangfang , Xuan Yang , Hou Zhaoyuan , Cui Yongping , Cao Liu , Li Xiaotao , Zhang Shengping , Wang Chuangui
Published: October 2015

Centrosome amplification is frequent in cancer, but the underlying mechanisms remain unclear. Here we report that disruption of the Kruppel-like factor 14 (KLF14) gene in mice causes centrosome amplification, aneuploidy and spontaneous tumorigenesis. Molecularly, KLF14 functions as a transcriptional repressor of Plk4, a polo-like kinase whose overexpression induces centrosome overduplication. Transient knockdown of KLF14 is sufficient to induce Plk4-directed centrosome amplification. Clinically, KLF14 transcription is significantly downregulated, whereas Plk4 transcription is upregulated in multiple types of cancers, and there exists an inverse correlation between KLF14 and Plk4 protein expression in human breast and colon cancers. Moreover, KLF14 depletion promotes AOM/DSS-induced colon tumorigenesis. Our findings reveal that KLF14 reduction serves as a mechanism leading to centrosome amplification and tumorigenesis. On the other hand, forced expression of KLF14 leads to mitotic catastrophe. Collectively, our findings identify KLF14 as a tumour suppressor and highlight its potential as biomarker and therapeutic target for cancer.
Effect of interfaces on the nearby Brownian motion
Authors: Huang Kai , Szlufarska Izabela
Published: October 2015

Near-boundary Brownian motion is a classic hydrodynamic problem of great importance in a variety of fields, from biophysics to micro-/nanofluidics. However, owing to challenges in experimental measurements of near-boundary dynamics, the effect of interfaces on Brownian motion has remained elusive. Here we report a computational study of this effect using μs-long large-scale molecular dynamics simulations and our newly developed Green–Kubo relation for friction at the liquid–solid interface. Our computer experiment unambiguously reveals that the t−3/2 long-time decay of the velocity autocorrelation function of a Brownian particle in bulk liquid is replaced by a t−5/2 decay near a boundary. We discover a general breakdown of traditional no-slip boundary condition at short time scales and we show that this breakdown has a profound impact on the near-boundary Brownian motion. Our results demonstrate the potential of Brownian-particle-based micro-/nanosonar to probe the local wettability of liquid–solid interfaces.
Analyzing historical trends in breast cancer biomarker expression: a feasibility study (1947–2009)
Authors: Krieger Nancy , Habel Laurel A , Waterman Pamela D , Shabani Melina , Ellison-Loschmann Lis , Achacoso Ninah S , Acton Luana , Schnitt Stuart J
Published: October 2015

Background/Objectives:

Determining long-term trends in tumor biomarker expression is essential for understanding aspects of tumor biology amenable to change. Limiting the availability of such data, currently used assays for biomarkers are relatively new. For example, assays for the estrogen receptor (ER), which are the oldest, extend back only to the 1970s.

Methods:

To extend scant knowledge about the feasibility of obtaining long-term data on tumor biomarkers, we randomly selected 60 breast cancer cases (10 per decade) diagnosed between 1947–2009 among women members of the Kaiser Permanente Northern California health plan to obtain and analyze their formalin-fixed paraffin-embedded (FFPE) tumor specimens. For each tumor specimen, we created duplicate tissue microarrays for analysis.

Results:

We located tumor blocks and pathology reports for 50 of the 60 cases (83%), from which we randomly sampled 5 cases per decade for biomarker analysis (n=30). All 30 cases displayed excellent morphology and exhibited biomarkers compatible with histologic type and grade. Test–retest reliability was also excellent: 100% for ER; 97% for human epidermal growth factor receptor 2 and epidermal growth factor receptor; 93% for progesterone receptor and cytokeratin 5/6; and 90% for Ki67 and molecular phenotype; the kappa statistic was excellent (>0.9) for 4 of the 7 biomarkers, strong (0.6–0.8) for 2, and fair for only 1 (owing to low prevalence).

Conclusions:

These results indicate immunostaining for biomarkers commonly used to evaluate breast cancer biology and assign surrogate molecular phenotypes can reliably be employed on archival FFPE specimens up to 60 years old.
Biobanking of patient and patient-derived xenograft ovarian tumour tissue: efficient preservation with low and high fetal calf serum based methods
Authors: Alkema Nicolette G. , Tomar Tushar , Duiker Evelien W. , Jan Meersma Gert , Klip Harry , van der Zee Ate G. J. , Wisman G. Bea A. , de Jong Steven
Published: October 2015

Using patient-derived xenografts (PDXs) for preclinical cancer research demands proper storage of tumour material to facilitate logistics and to reduce the number of animals needed. We successfully established 45 subcutaneous ovarian cancer PDXs, reflecting all histological subtypes, with an overall take rate of 68%. Corresponding cells from mouse replaced human tumour stromal and endothelial cells in second generation PDXs as demonstrated with mouse-specific vimentin and CD31 immunohistochemical staining. For biobanking purposes two cryopreservation methods, a fetal calf serum (FCS)-based (95%v/v) “FCS/DMSO” protocol and a low serum-based (10%v/v) “vitrification” protocol were tested. After primary cryopreservation, tumour take rates were 38% and 67% using either the vitrification or FCS/DMSO-based cryopreservation protocol, respectively. Cryopreserved tumour tissue of established PDXs achieved take rates of 67% and 94%, respectively compared to 91% using fresh PDX tumour tissue. Genotyping analysis showed that no changes in copy number alterations were introduced by any of the biobanking methods. Our results indicate that both protocols can be used for biobanking of ovarian tumour and PDX tissues. However, FCS/DMSO-based cryopreservation is more successful. Moreover, primary engraftment of fresh patient-derived tumours in mice followed by freezing tissue of successfully established PDXs is the preferred way of efficient ovarian cancer PDX biobanking.
Time-scales of hydrological forcing on the geochemistry and bacterial community structure of temperate peat soils
Authors: Nunes Flavia L. D. , Aquilina Luc , de Ridder Jo , Francez André-Jean , Quaiser Achim , Caudal Jean-Pierre , Vandenkoornhuyse Philippe , Dufresne Alexis
Published: October 2015

Peatlands are an important global carbon reservoir. The continued accumulation of carbon in peatlands depends on the persistence of anoxic conditions, in part induced by water saturation, which prevents oxidation of organic matter and slows down decomposition. Here we investigate how and over what time scales the hydrological regime impacts the geochemistry and the bacterial community structure of temperate peat soils. Peat cores from two sites having contrasting groundwater budgets were subjected to four controlled drought-rewetting cycles. Pore water geochemistry and metagenomic profiling of bacterial communities showed that frequent water table drawdown induced lower concentrations of dissolved carbon, higher concentrations of sulfate and iron and reduced bacterial richness and diversity in the peat soil and water. Short-term drought cycles (3–9 day frequency) resulted in different communities from continuously saturated environments. Furthermore, the site that has more frequently experienced water table drawdown during the last two decades presented the most striking shifts in bacterial community structure, altering biogeochemical functioning of peat soils. Our results suggest that the increase in frequency and duration of drought conditions under changing climatic conditions or water resource use can induce profound changes in bacterial communities, with potentially severe consequences for carbon storage in temperate peatlands.
Alleviation of skin inflammation after Lin− cell transplantation correlates with their differentiation into myeloid-derived suppressor cells
Authors: Jeong Ryu Su , Ju Ji-Min , Kim Woojin , Bum Kim Min , Hee Oh Kuen , Sup Lee Dong , Lee Hakmo , Eun Oh Ju , Soo Park Kyong , Young Choi Eun
Published: October 2015

To understand the cellular mechanism underlying the therapeutic effects exerted by hematopoietic stem cell transplantation in the repair of tissue damage, we investigated the in vivo dynamics of bone marrow (BM) lineage-negative (Lin−) cells transplanted into mice with hyper sensitivity dermatitis. Longitudinal in vivo imaging and flow cytometry analyses revealed that Lin− cells home directly to inflamed skin within 6 h, where they undergo extensive expansion with the peak on day 14 post-transplantation and preferential differentiation into CD11b+Ly6GintLy6C+ cells by day 7. Cells with phenotypic profiles of neutrophils, macrophages and DCs appeared in inflamed skin on day 14. Progenies of transplanted Lin− cells showed similar kinetics of expansion and myeloid differentiation in BM. However, differentiation into CD11b+Ly6GintLy6C+ cells in the inflamed skin on day 7 was more skewed toward CD115+ cells (≥60%) with immune suppressive function and higher expression levels of iNOS, arginase and IL-10, compared with those in the BM. Transplantation of Lin− cells reduced the levels of Cd3 transcript and CD4+/CD8+ cells in inflamed skin. These results demonstrate differentiation of transplanted Lin− cells into myeloid-derived suppressor cells in inflamed skin to be the basis of the alleviation of skin inflammation after Lin− cell transplantation.
Three-Dimensional (3D) Bicontinuous Hierarchically Porous Mn2O3 Single Crystals for High Performance Lithium-Ion Batteries
Authors: Huang Shao-Zhuan , Jin Jun , Cai Yi , Li Yu , Deng Zhao , Zeng Jun-Yang , Liu Jing , Wang Chao , Hasan Tawfique , Su Bao-Lian
Published: October 2015

Bicontinuous hierarchically porous Mn2O3 single crystals (BHP-Mn2O3-SCs) with uniform parallelepiped geometry and tunable sizes have been synthesized and used as anode materials for lithium-ion batteries (LIBs). The monodispersed BHP-Mn2O3-SCs exhibit high specific surface area and three dimensional interconnected bimodal mesoporosity throughout the entire crystal. Such hierarchical interpenetrating porous framework can not only provide a large number of active sites for Li ion insertion, but also good conductivity and short diffusion length for Li ions, leading to a high lithium storage capacity and enhanced rate capability. Furthermore, owing to their specific porosity, these BHP-Mn2O3-SCs as anode materials can accommodate the volume expansion/contraction that occurs with lithium insertion/extraction during discharge/charge processes, resulting in their good cycling performance. Our synthesized BHP-Mn2O3-SCs with a size of ~700 nm display the best electrochemical performance, with a large reversible capacity (845 mA h g−1 at 100 mA g−1 after 50 cycles), high coulombic efficiency (>95%), excellent cycling stability and superior rate capability (410 mA h g−1 at 1 Ag−1). These values are among the highest reported for Mn2O3-based bulk solids and nanostructures. Also, electrochemical impedance spectroscopy study demonstrates that the BHP-Mn2O3-SCs are suitable for charge transfer at the electrode/electrolyte interface.