bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization‐based Full Body Control for the DARPA Robotics Challenge
Authors: Feng Siyuan , Whitman Eric , Xinjilefu X. , Atkeson Christopher G.
Published: January 2015

We describe our full body humanoid control approach developed for the simulation phase of the DARPA Robotics Challenge (DRC), as well as the modifications made for the DARPA Robotics Challenge Trials. We worked with the Boston Dynamics Atlas robot. Our approach was initially targeted at walking, and it consisted of two levels of optimization: a high‐level trajectory optimizer that reasons about center of mass and swing foot trajectories, and a low‐level controller that tracks those trajectories by solving floating base full body inverse dynamics using quadratic programming. This controller is capable of walking on rough terrain, and it also achieves long footsteps, fast walking speeds, and heel‐strike and toe‐off in simulation. During development of these and other whole body tasks on the physical robot, we introduced an additional optimization component in the low‐level controller, namely an inverse kinematics controller. Modeling and torque measurement errors and hardware features of the Atlas robot led us to this three‐part approach, which was applied to three tasks in the DRC Trials in December 2013.
Melting Properties and Viscosity of SiO2‐CaO‐Al2O3‐B2O3 System
Authors: Wang Lin , Cui Yaru , Yang Jian , Zhang Chen , Cai Dexiang , Zhang Jianqiang , Sasaki Yasushi , Ostrovski Oleg
Published: January 2015

This paper investigated melting properties and viscosity of SiO2‐CaO‐Al2O3‐B2O3 fluxes with a mass ratio of CaO/SiO2 from 0.83 to 1.5 and B2O3 content from 5 to 9 wt%. Melting properties of these fluxes were studied using the hot stage microscopy method; viscosity was measured using the rotating cylinder method. Break temperature was also determined from the viscosity change with temperature in flux cooling process. Equilibrium liquidus temperature was calculated using FactSage. Increase in CaO/SiO2 ratio was found to decrease hemispherical temperature and viscosity. The addition of B2O3 did not significantly affect hemispherical temperature but decreased the flux viscosity. Viscosity was analyzed in relation to the flux structure. The increase of the CaO/SiO2 ratio reduced the degree of flux polymerization, and B2O3 apparently acted as a weak network modifier under the low concentration of B2O3. The experimental viscosity was in a good agreement with calculated viscosity using the modified NPL model.
Long‐Term Outcomes of Open and Video‐Assisted Thoracoscopic Lung Lobectomy for the Treatment of Early Stage Non‐small Cell Lung Cancer are Similar: A Propensity‐Matched Study
Authors: Murakawa Tomohiro , Ichinose Junji , Hino Haruaki , Kitano Kentaro , Konoeda Chihiro , Nakajima Jun
Published: January 2015

Background

Generally, in retrospective studies, favourable short‐ and long‐term outcomes for patients after lung lobectomy for early stage non‐small cell lung cancer (NSCLC) using video‐assisted thoracoscopic surgery (VATS) have been reported. However, the interpretation of lung lobectomy outcomes may be biased in retrospective settings.

Methods

We retrospectively reviewed patients who underwent lung lobectomy for cT1‐2N0M0 NSCLC from 2001 to 2010. The outcomes of patients who underwent VATS lobectomy were compared to those who underwent open lobectomy before and after performing propensity score matching. Preoperative covariates were entered when developing the propensity score‐matching model.

Results

This study reviewed the outcomes of 101 VATS patients and 184 open lobectomy patients. Before propensity score matching, the VATS group had a higher mean age (p < 0.0001), smaller solid tumour size (p = 0.0042), similar whole tumour size (p = 0.2082), and larger tumour‐disappearance ratio (p = 0.0007). The VATS group had a shorter mean operation time (p = 0.0002), less blood loss (p < 0.0001), shorter chest tube duration (p = 0.0002), and shorter hospital stay (p < 0.0001). As for long‐term outcomes, the VATS group had higher disease‐free, disease‐specific, and overall survival rates (p values by log‐rank test: 0.0049, 0.0154, and 0.032, respectively). After propensity score matching, all differences, except operation time, blood loss, chest tube duration, and hospital stay, were no longer significant.

Conclusions

VATS lobectomy is less invasive than open lobectomy, but in terms of survival outcomes, VATS lobectomy was oncologically equivalent to open lobectomy. The oncological benefit of VATS reported by retrospective studies might be overestimated.
A delayed oscillator model for the quasi-periodic multidecadal variability of the NAO
Authors: Sun Cheng , Li Jianping , Jin Fei-Fei
Published: January 2015

Wavelet analysis of the annual North Atlantic Oscillation (NAO) index back to 1659 reveals a significant frequency band at about 60 years. Recent NAO decadal variations, including the increasing trend during 1960–1990 and decreasing trend since the mid-1990s, can be well explained by the approximate 60-year cycle. This quasi 60-year oscillation of the NAO is realistically reproduced in a long-term control simulation with version 4 of the Community Climate System Model, and the possible mechanisms are further investigated. The positive NAO forces the strengthening of the Atlantic meridional overturning circulation (AMOC) and induces a basin-wide uniform sea surface temperature (SST) warming that corresponds to the Atlantic multidecadal oscillation (AMO). The SST field exhibits a delayed response to the preceding enhanced AMOC, and shows a pattern similar to the North Atlantic tripole (NAT), with SST warming in the northern North Atlantic and cooling in the southern part. This SST pattern (negative NAT phase) may lead to an atmospheric response that resembles the negative NAO phase, and subsequently the oscillation proceeds, but in the opposite sense. Based on these mechanisms, a simple delayed oscillator model is established to explain the quasi-periodic multidecadal variability of the NAO. The magnitude of the NAO forcing of the AMOC/AMO and the time delay of the AMOC/AMO feedback are two key parameters of the delayed oscillator. For a given set of parameters, the quasi 60-year cycle of the NAO can be well predicted. This delayed oscillator model is useful for understanding of the oscillatory mechanism of the NAO, which has significant potential for decadal predictions as well as the interpretation of proxy data records.
CALCULATING VARIABLE ANNUITY LIABILITY “GREEKS” USING MONTE CARLO SIMULATION
Authors: Cathcart Mark J. , Lok Hsiao Yen , McNeil Alexander J. , Morrison Steven
Published: January 2015

The implementation of hedging strategies for variable annuity products requires the calculation of market risk sensitivities (or “Greeks”). The complex, path-dependent nature of these products means that these sensitivities are typically estimated by Monte Carlo methods. Standard market practice is to use a “bump and revalue” method in which sensitivities are approximated by finite differences. As well as requiring multiple valuations of the product, this approach is often unreliable for higher-order Greeks, such as gamma, and alternative pathwise (PW) and likelihood-ratio estimators should be preferred. This paper considers a stylized guaranteed minimum withdrawal benefit product in which the reference equity index follows a Heston stochastic volatility model in a stochastic interest rate environment. The complete set of first-order sensitivities with respect to index value, volatility and interest rate and the most important second-order sensitivities are calculated using PW, likelihood-ratio and mixed methods. It is observed that the PW method delivers the best estimates of first-order sensitivities while mixed estimation methods deliver considerably more accurate estimates of second-order sensitivities; moreover there are significant computational gains involved in using PW and mixed estimators rather than simple BnR estimators when many Greeks have to be calculated.
Predicting Recurrence after Chronic Subdural Haematoma Drainage
Authors: Jack Andrew , O’Kelly Cian , McDougall Cameron , Max Findlay J.
Published: January 2015

Background: Recurrence of chronic subdural haematomas (CSDHs) after surgical drainage is a significant problem with rates up to 20%. This study focuses on determining factors predictive of haematoma recurrence and presents a scoring system stratifying recurrence risk for individual patients. Methods: Between the years 2005 and 2009, 331 consecutive patients with CSDHs treated with surgery were included in this study. Univariate and multivariate analyses were performed searching for risk factors of increased post-operative haematoma volume and haematoma recurrence requiring repeat drainage. Results: We found a 12% reoperation rate. CSDH septation (seen on computed tomogram scan) was found to be an independent risk factor for recurrence requiring reoperation (p=0.04). Larger post-operative subdural haematoma volume was also significantly associated with requiring a second drainage procedure (p<0.001). Independent risk factors of larger post-operative haematoma volume included septations within a CSDH (p<0.01), increased pre-operative haematoma volume (p<0.01), and a greater amount of parenchymal atrophy (p=0.04). A simple scoring system for quantifying recurrence risk was created and validated based on patient age (< or ≥80 years), haematoma volume (< or ≥160cc), and presence of septations within the subdural collection (yes or no). Conclusion: Septations within CSDHs are associated with larger post-operative residual haematoma collections requiring repeat drainage. When septations are clearly visible within a CSDH, craniotomy might be more suitable as a primary procedure as it allows greater access to a septated subdural collection. Our proposed scoring system combining haematoma volume, age, and presence of septations might be useful in identifying patients at higher risk for recurrence.
Risk Factors forMycobacterium abscessussubsp.bolletiiInfection After Laparoscopic Surgery During an Outbreak in Brazil
Authors: Baruque Villar Gabriela , de Mello Freitas Felipe Teixeira , Pais Ramos Jesus , Dias Campos Carlos Eduardo , de Souza Caldas Paulo Cesar , Santos Bordalo Fernanda , Amorim Ramos Tatyana Costa , do Nascimento Pereira Vívian , Cordeiro-Santos Marcelo , Abdalla Santos Joao Hugo , Coelho Motta Glauco , Gomes Suzie Marie , Mendes de Souza Verena Maria , de Araujo Wildo Navegantes
Published: January 2015

OBJECTIVE

To identify risk factors related toMycobacterium abscessussubsp.bolletiiinfection during an outbreak, associated with laparoscopic surgery and to propose recommendations for preventing new cases.

DESIGN

A retrospective cohort study.

SETTING

A private hospital in Manaus, Brazil.

PATIENTS

A cohort of 222 patients who underwent laparoscopic surgery between July 2009 and August 2010 by a single surgical team.

METHODS

We collected information about the patients and the surgical procedure using a standard form. We included sex, age, and variables withP≤0.2 in the bivariate analysis in a logistic regression model. Additionally, we reviewed the procedures for reprocessing the laparoscopic surgery equipment, and the strains obtained with culture were identified by molecular methods.

RESULTS

We recorded 60 (27%) cases of infection. After multivariate analysis, the duration of surgery beyond 1 hour (odds ratio [OR] 2.4; 95% confidence interval [CI] 1.2–4.5), not to have been the first operated patient on a given day (OR, 2.7; 95% CI, 1.4–5.2), and the use of permanent trocar (OR, 2.2; 95% CI, 1.1–4.2) were associated with infection. We observed that the surgical team attempted to sterilize the equipment in glutaraldehyde solution when sanitary authorities had already prohibited it. Eleven strains presented 100% DNA identity with a single strain, known as BRA100 clone.

CONCLUSIONS

Because contaminated material can act as vehicle for infection, ensuring adequate sterilization processing of video-assisted surgery equipment was crucial to stopping this single clonal outbreak of nonturbeculous mycobacteria in Brazil.

Infect Control Hosp Epidemiol 2015;36(1): 81–86
Evaluation of a Pulsed Xenon Ultraviolet Disinfection System for Reduction of Healthcare-Associated Pathogens in Hospital Rooms
Authors: Nerandzic Michelle M. , Thota Priyaleela , Sankar C. Thriveen , Jencson Annette , Cadnum Jennifer L. , Ray Amy J. , Salata Robert A. , Watkins Richard R. , Donskey Curtis J.
Published: January 2015

OBJECTIVE

To determine the effectiveness of a pulsed xenon ultraviolet (PX-UV) disinfection device for reduction in recovery of healthcare-associated pathogens.

SETTING

Two acute-care hospitals.

METHODS

We examined the effectiveness of PX-UV for killing ofClostridium difficilespores, methicillin-resistantStaphylococcus aureus(MRSA), and vancomycin-resistantEnterococcus(VRE) on glass carriers and evaluated the impact of pathogen concentration, distance from the device, organic load, and shading from the direct field of radiation on killing efficacy. We compared the effectiveness of PX-UV and ultraviolet-C (UV-C) irradiation, each delivered for 10 minutes at 4 feet. In hospital rooms, the frequency of native pathogen contamination on high-touch surfaces was assessed before and after 10 minutes of PX-UV irradiation.

RESULTS

On carriers, irradiation delivered for 10 minutes at 4 feet from the PX-UV device reduced recovery ofC. difficilespores, MRSA, and VRE by 0.55±0.34, 1.85±0.49, and 0.6±0.25 log10colony-forming units (CFU)/cm2, respectively. Increasing distance from the PX-UV device dramatically reduced killing efficacy, whereas pathogen concentration, organic load, and shading did not. Continuous UV-C achieved significantly greater log10CFU reductions than PX-UV irradiation on glass carriers. On frequently touched surfaces, PX-UV significantly reduced the frequency of positiveC. difficile, VRE, and MRSA culture results.

CONCLUSIONS

The PX-UV device reduced recovery of MRSA,C. difficile, and VRE on glass carriers and on frequently touched surfaces in hospital rooms with a 10-minute UV exposure time. PX-UV was not more effective than continuous UV-C in reducing pathogen recovery on glass slides, suggesting that both forms of UV have some effectiveness at relatively short exposure times.

Infect Control Hosp Epidemiol 2014;00(0): 1–6
Comparison of Immune Response to the Influenza Vaccine in Obese and Nonobese Healthcare Workers
Authors: Sweet Michael A. , McCullers Jonathan A. , Lasala Paul R. , Briggs Frank E. , Smithmyer Anne , Khakoo Rashida A.
Published: January 2015

OBJECTIVE

To determine whether there is a difference in antibody titers and functionality after receipt of the influenza vaccine for obese versus nonobese healthcare workers (HCW).

DESIGN

Prospective observational study.

SETTING

Tertiary medical center.

PARTICIPANTS

Healthcare workers.

METHODS

Baseline influenza antibody titers for obese and nonobese HCW were recorded during the hospital’s 2011 annual influenza vaccination day and follow-up antibody titers were measured 4 weeks later. Antibodies were measured using the hemagglutination inhibition assay and functionality was measured using the micro-neutralization method.

RESULTS

Of 200 initial HCWs, 190 completed the study (97 obese and 93 nonobese). Seroprotection after immunization was not significantly different for nonobese compared with obese HCW for each strain (influenza A [H1N1], 99% and 99%; influenza A [H3N2], 100% and 99%; and influenza B, 67% and 71%, respectively)

All geometric mean titers measured by micro-neutralization showed statistically significant increases in activity. In comparison, there was no difference in the 4-fold increase in H1N1 or B titers. There was a significant difference in the 4-fold increase of H3N2 titers between the nonobese and obese HCWs (82/93 [88%] vs 64/97 [66%], P=.003)

In an ad hoc analysis we found that obese HCWs had a statistically greater number of 4-fold decreases in titers with H1N1 and H3N2.

CONCLUSIONS

There was no significant difference in protection from influenza between obese and nonobese HCWs after immunization.

Infect Control Hosp Epidemiol 2014;00(0): 1–5
State Law Mandates for Reporting of Healthcare-Associated Clostridium difficile Infections in Hospitals
Authors: Reagan Julie , Herzig Carolyn T.A. , Pogorzelska-Maziarz Monika , Dick Andrew W. , Stone Patricia W. , Divya Srinath JD
Published: January 2015

US state and territorial laws were reviewed to identify Clostridium difficile infection reporting mandates. Twenty states require reporting either under state law or by incorporating federal Centers for Medicare & Medicaid Services’ reporting requirements. Although state law mandates are more common, the incorporation of federal reporting requirements has been increasing.

Infect Control Hosp Epidemiol 2014;00(0): 1–3
Overtreatment of Asymptomatic Bacteriuria: Identifying Targets for Improvement
Authors: Hartley Sarah , Valley Staci , Kuhn Latoya , Washer Laraine L. , Gandhi Tejal , Meddings Jennifer , Chenoweth Carol , Malani Anurag N. , Saint Sanjay , Srinivasan Arjun , Flanders Scott A.
Published: January 2015

Treatment of asymptomatic bacteriuria contributes to antimicrobial overuse in hospitalized patients. Indications for urine culture, treatment, and targets for improvement were evaluated in 153 patients. Drivers of antimicrobial overuse included fever with an alternative source, altered mental status, and leukocytosis, which led 435 excess days of antimicrobial therapy.

Infect Control Hosp Epidemiol 2014;00(0): 1–4
Impact of Universal Gowning and Gloving on Health Care Worker Clothing Contamination
Authors: Williams Calvin , McGraw Patty , Schneck Elyse E. , LaFae Anna , Jacob Jesse T. , Moreno Daniela , Reyes Katherine , Fernando Cubillos G. , Kett Daniel H. , Estrella Ronald , Morgan Daniel J. , Harris Anthony D. , Drees Marci
Published: January 2015

OBJECTIVE

To determine whether gowning and gloving for all patient care reduces contamination of healthcare worker (HCW) clothing, compared to usual practice.

DESIGN

Cross-sectional surveys.

SETTING

Five study sites were recruited from intensive care units (ICUs) randomized to the intervention arm of the Benefits of Universal Gown and Glove (BUGG) study.

PARTICIPANTS

All HCWs performing direct patient care in the study ICUs were eligible to participate.

METHODS

Surveys were performed first during the BUGG intervention study period (July–September 2012) with universal gowning/gloving and again after BUGG study conclusion (October–December 2012), with resumption of usual care. During each phase, HCW clothing was sampled at the beginning and near the end of each shift. Cultures were performed using broth enrichment followed by selective media. Acquisition was defined as having a negative clothing culture for samples taken at the beginning of a shift and positive clothing culture at for samples taken at the end of the shift.

RESULTS

A total of 348 HCWs participated (21–92 per site), including 179 (51%) during the universal gowning/gloving phase. Overall, 51 (15%) HCWs acquired commonly pathogenic bacteria on their clothing: 13 (7.1%) HCWs acquired bacteria during universal gowning/gloving, and 38 (23%) HCWs acquired bacteria during usual care (odds ratio [OR], 0.3; 95% confidence interval [CI], 0.2–0.6). Pathogens identified includedS. aureus(25 species, including 7 methicillin-resistantS. aureus[MRSA]),Enterococcusspp. (25, including 1 vancomycin-resistantEnterococcus[VRE]),Pseudomonasspp. (4),Acinetobacterspp. (4), andKlebsiella(2).

CONCLUSION

Nearly 25% of HCWs practicing usual care (gowning and gloving only for patients with known resistant bacteria) contaminate their clothing during their shift. This contamination was reduced by 70% by gowning and gloving for all patient interactions.

Infect Control Hosp Epidemiol 2014;00(0): 1–7
Postoperative Burden of Hospital-Acquired Clostridium difficile Infection
Authors: Abdelsattar Zaid M. , Krapohl Greta , Alrahmani Layan , Banerjee Mousumi , Krell Robert W. , Wong Sandra L. , Campbell Darrell A. , Aronoff David M. , Hendren Samantha
Published: January 2015

OBJECTIVE

Clostridium difficile infection (CDI) is a common hospital-acquired infection. Previous reports on the incidence, risk factors, and impact of CDI on resources in the surgical population are limited. In this context, we study CDI across diverse surgical settings.

METHODS

We prospectively identified patients with laboratory-confirmed postoperative CDI after 40 different general, vascular, or gynecologic surgeries at 52 academic and community hospitals between July 2012 and September 2013. We used multivariable regression models to identify CDI risk factors and to determine the impact of CDI on resource utilization.

RESULTS

Of 35,363 patients, 179 (0.51%) developed postoperative CDI. The highest rates of CDI occurred after lower-extremity amputation (2.6%), followed by bowel resection or repair (0.9%) and gastric or esophageal operations (0.7%). Gynecologic and endocrine operations had the lowest rates (0.1% and 0%, respectively). By multivariable analyses, older age, chronic immunosuppression, hypoalbuminemia (≤3.5 g/dL), and preoperative sepsis were associated with CDI. Use of prophylactic antibiotics was not independently associated with CDI, neither was sex, body mass index (BMI), surgical priority, weight loss, or comorbid conditions. Three procedure groups had higher odds of postoperative CDI: lower-extremity amputations (adjusted odds ratio [aOR], 3.5; P=.03), gastric or esophageal operations (aOR, 2.1; P=.04), and bowel resection or repair (aOR, 2; P=.04). Postoperative CDI was independently associated with increased length of stay (mean, 13.7 d vs 4.5 d), emergency department presentations (18.9 vs 9.1%) and readmissions (38.9% vs 7.2%, all P<.001).

CONCLUSIONS

Incidence of postoperative CDI varies by surgical procedure. Postoperative CDI is also associated with higher rates of extended length of stay, emergency room presentations, and readmissions, which places a potentially preventable burden on hospital resources.

Infect Control Hosp Epidemiol 2015;36(1): 40–46
The association between parental and adolescent substance misuse: findings from the Irish CASE study
Authors: Keeley Helen S. , Mongwa T. , Corcoran P.
Published: January 2015

Background

Self-report data from 2716 adolescents aged 15–17 years old in Irish schools were analysed to consider the association between psycho-social factors and the presence of adolescent substance and alcohol abuse, with an emphasis on family circumstances.

Methods

Data were collected using the ‘Lifestyle and Coping Questionnaire’ which includes questions about lifestyle, coping, problems, alcohol and drug use, deliberate self-harm, depression, anxiety, impulsivity and self-esteem. Two additional questions were added to the standard questionnaire regarding parental substance misuse.

Results

Adolescent substance abuse was more common in boys; parental substance misuse increased the risk of adolescent abuse of alcohol and drugs; the increased risk was marginally higher if the parental substance abuse was maternal rather than paternal; the increased risk was higher if the parental substance abuse affected both rather than one of the parents, especially regarding adolescent drug abuse; the magnitude of the increased risk was similar for boys and girls. Parental substance misuse increased the risk of adolescent substance abuse even after adjusting for other family problems and the adolescent’s psychological characteristics.

Conclusions

This study indicates that parental substance misuse affects the development of both alcohol and drug misuse in adolescent children independent of other family problems and the psychological characteristics of the adolescent. A wider perspective is needed, including societal and family issues, especially parental behaviour, when attempting to reduce risk of adolescent addiction. The impact on children of parental substance misuse also needs consideration in clinical contexts.
Rock dissolution patterns and geochemical shutdown of –brine–carbonate reactions during convective mixing in porous media
Authors: Fu X. , Cueto-Felgueroso L. , Bolster D. , Juanes R.
Published: January 2015

Motivated by the process of $\text{CO}_{2}$ convective mixing in porous media, here we study the formation of rock-dissolution patterns that arise from geochemical reactions during Rayleigh–Bénard–Darcy convection. Under the assumption of instantaneous chemical equilibrium, we adopt a formulation of the local reaction rate as a function of scalar dissipation rate, a measure that depends solely on flow and transport, and chemical speciation, which is a measure that depends only on the equilibrium thermodynamics of the chemical system. We use high-resolution simulations to examine the interplay between the density-driven hydrodynamic instability and the rock dissolution reactions, and analyse the impact of geochemical reactions on the macroscopic mass exchange rate. We find that dissolution of carbonate rock initiates in regions of locally high mixing, but that the geochemical reaction shuts down significantly earlier than shutdown of convective mixing. This early shutdown feature reflects the important role that chemical speciation plays in this hydrodynamics–reaction coupled process. Finally, we extend our analysis to three dimensions and explore the morphology of dissolution patterns in three dimensions.
Transition of transient channel flow after a change in Reynolds number
Authors: He S. , Seddighi M.
Published: January 2015

It has previously been shown that the transient flow in a channel following a step increase of Reynolds number from 2800 to 7400 (based on channel half-height and bulk velocity) is effectively a laminar–turbulent bypass transition even though the initial flow is turbulent (He & Seddighi, J. Fluid Mech., vol. 715, 2013, pp. 60–102). In this paper, it is shown that the transient flow structures exhibit strong contrasting characteristics in large and small flow perturbation scenarios. When the increase of Reynolds number is large, the flow is characterized by strong elongated streaks during the initial period, followed by the occurrence and spreading of isolated turbulent spots, as shown before. By contrast, the flow appears to evolve progressively and the turbulence regeneration process remains largely unchanged during the flow transient when the Reynolds number ratio is low, and streaks do not appear to play a significant role. Despite the major apparent differences in flow structures, the transient flow under all conditions considered is unambiguously characterized by laminar–turbulent transition, which exhibits itself clearly in various flow statistics. During the pre-transition period, the time-developing boundary layers in all the cases show a strong similarity to each other and follow closely the Stokes solution for a transient laminar boundary layer. The streamwise fluctuating velocity also shows good similarity in the various cases, irrespective of the appearance of elongated streaks or not, and the maximum energy growth exhibits a linear rate similar to that in a spatially developing boundary layer. The onset of transition is clearly definable in all cases using the minimum friction factor, and the critical time thus defined is strongly correlated with the free-stream turbulence in a power-law form.
Thermomagnetic convection in a layer of ferrofluid placed in a uniform oblique external magnetic field
Authors: Rahman Habibur , Suslov Sergey A.
Published: January 2015

Linear stability of magnetoconvection of a ferromagnetic fluid contained between two infinite differentially heated non-magnetic plates in the presence of an oblique uniform external magnetic field is studied in zero gravity conditions. The thermomagnetic convection that arises is caused by the spatial variation of magnetisation occurring due to its dependence on the temperature. The critical values of the governing parameters at which the transition between motionless and convective states is observed are determined for various field inclination angles and for fluid magnetic parameters that are consistently chosen from a realistic experimental range. It is shown that, similar to natural paramagnetic fluids, the most prominent convection patterns align with the in-layer component of the applied magnetic field but in contrast to such paramagnetic fluids the instability patterns detected in ferrofluids can be oscillatory. It is also found that, contrary to paramagnetic fluids, the stability characteristics of magnetoconvection in ferrofluids depend on the magnitude of the applied field which becomes an additional parameter of the problem. This is shown to be due to the nonlinearity of the magnetic field distribution within the ferrofluid.
What We Can Learn From Hearing Parents of Deaf Children
Authors: Flaherty Mary
Published: January 2015

Hearing parents of deaf children face stresses and demands related to parenting a deaf child, including difficult choices about language, technologies, education and identity for their children (Marschark, 1997). To date, few researchers have discussed the unique challenges faced by this group. Through a series of semistructured, in-depth interviews with 18 parents, this study investigated the experiences of hearing parents of deaf children spanning various life stages. A phenomenological approach identified 5 themes most pertinent to understanding their experiences. Each theme offers insight, particularly for professionals, into the distinctive issues that might arise at the time of diagnosis of deafness and reveals the challenges hearing parents face when confronted with a barrage of decisions, including choice of oral or sign language, mainstream or special deaf education, and identity with the hearing or Deaf community. The central message from this work is to inform hearing parents of deaf children and professionals working with these parents of the likely challenges that they may face.
Some Weighted Group Algebras are Operator Algebras
Authors: Lee Hun Hee , Samei Ebrahim , Spronk Nico
Published: January 2015

Let G be a finitely generated group with polynomial growth, and let ω be a weight, i.e. a sub-multiplicative function on G with positive values. We study when the weighted group algebra ℓ1 (G, ω) is isomorphic to an operator algebra. We show that ℓ1 (G, ω) is isomorphic to an operator algebra if ω is a polynomial weight with large enough degree or an exponential weight of order 0 < α < 1. We demonstrate that the order of growth of G plays an important role in this problem. Moreover, the algebraic centre of ℓ1 (G, ω) is isomorphic to a Q-algebra, and hence satisfies a multi-variable von Neumann inequality. We also present a more detailed study of our results when G consists of the d-dimensional integers ℤd or the three-dimensional discrete Heisenberg group ℍ3(ℤ). The case of the free group with two generators is considered as a counter-example of groups with exponential growth.
Age, growth and reproduction of European hake (Merluccius merluccius (Linn., 1758)) in the Central Aegean Sea, Turkey
Authors: Soykan Ozan , İlkyaz Akin T. , Metın Gülnur , Kinacigıl H. Tuncay
Published: January 2015

Specimens of European hake were collected by a traditional demersal trawl between July 2004 and June 2007 from İzmir Bay, Central Aegean Sea. A total of 2108 individuals were sampled during the study and the female: male sex ratio of the stock was 1:0.89. The length–weight relationship was W = 0.00341L3.24 (R2 = 0.994) for all individuals. A high gonadosomatic index was evident over most of the year but it was minimal from August to October. The estimated age composition was 1–5 years; the length and weight at infinity were calculated as L∞ = 54.53 cm and W∞ = 1455.77 g respectively. In addition, growth coefficient was found to be k = 0.315 y−1 and to = −0.223 y (R2 = 0.99). Total mortality ratio of the stock was calculated as Z = 1.539 y−1, while natural and fishing based mortality ratio were estimated as M = 0.579 y−1 and F = 0.959 y−1 respectively, with the exploitation ratio (E) of the stock estimated to be 0.624.
The influence of prior training on GPs’ attitudes to sickness absence certification post-fit note
Authors: Money Annemarie , Hann Mark , Turner Susan , Hussey Louise , Agius Raymond
Published: January 2015

Aim

To investigate the attitudes to health and work of general practitioners (GPs) with training in occupational medicine (OM) compared with non-OM trained GPs, since the introduction of the fit note.

Background

Changes to the UK sickness certification system since 2010 and the introduction of the fit note required GPs to change their focus to what patients can do, rather than what they cannot do in relation to work. In an effort to reduce the UK sickness absence burden, GPs completion of the fit note should help to keep people in work, or assist patients to return to work as quickly as possible after a period of absence.

Methods

Questionnaire data were collected via the 7th National General Practitioner Worklife Survey.

Findings

Results indicate that responses from GPs who had undertaken training in OM, and GPs having received some form of work and health training in the 12-month period before the study were associated with significantly more positive attitudes to patients’ returning to work and to the fit note. This study reveals evidence of a difference between trained and non-trained GPs in their attitude to the fit note, and to work and health generally. Further work investigating the effect of specific training in OM on the management and recognition of ill-health by GPs is recommended.
The special case of the three body problem, when gravitational potential is given as the Kislik potential
Authors: Shuvalova A. , Salnikova T.
Published: January 2015

In this paper we consider the special case of the planar circular restricted three-body problem by the example of the problem of the Earth, the Moon and a point mass, where the gravitational potentials of the Earth and the Moon are given as the Kislik potential. The Kislik potential takes into account the flattening of a celestial body on the poles. We find the relative equilibria solutions for a point mass and analyze their stability. We describe the difference between the obtained points and the classical solution of the three-body problem.
Modeling resonant trojan motions in planetary systems
Authors: Efthymiopoulos Christos , Páez Rocío I.
Published: January 2015

We consider the dynamics of a small trojan companion of a hypothetical giant exoplanet under the secular perturbations of additional planets. By a suitable choice of action-angle variables, the problem is amenable to the study of the slow modulation, induced by secular perturbations, to the dynamics of an otherwise called ‘basic’ Hamiltonian model of two degrees of freedom (planar case). We present this Hamiltonian decomposition, which implies that the slow chaotic diffusion at resonances is best described by the paradigm of modulational diffusion.
Impact flux of asteroids and water transport to the habitable zone in binary star systems
Authors: Bancelin D. , Pilat-Lohinger E. , Eggl S. , Dvorak R.
Published: January 2015

By now, observations of exoplanets have found more than 50 binary star systems hosting 71 planets. We expect these numbers to increase as more than 70% of the main sequence stars in the solar neighborhood are members of binary or multiple systems. The planetary motion in such systems depends strongly on both the parameters of the stellar system (stellar separation and eccentricity) and the architecture of the planetary system (number of planets and their orbital behaviour). In case a terrestrial planet moves in the so-called habitable zone (HZ) of its host star, the habitability of this planet depends on many parameters. A crucial factor is certainly the amount of water. We investigate in this work the transport of water from beyond the snow-line to the HZ in a binary star system and compare it to a single star system.
Eccentricity estimates in hierarchical triple systems
Authors: Georgakarakos Nikolaos , Eggl Siegfried
Published: January 2015

Perturbation theory in the three body problem has greatly advanced our ability to understand and model a variety of systems ranging from artificial satellites to stars and from extrasolar planets to asteroid-Jupiter interactions. In a series of papers, we developed an analytical technique for estimating the orbital eccentricity of the inner binary in hierarchical triple systems. The method combined the secular theory with calculations of short period terms. The derivation of the short term component was based on an expansion of the rate of change of the Runge-Lenz vector by using first order perturbation theory, while canonical perturbation theory was used to investigate the secular evolution of the system. In the present work we extend the calculation to the orbit of the outer binary. At the same time, we provide an improved version for some previous results. A post-Newtonian correction is included in our model. Our analytical estimates are compared with numerical and analytical results on the subject and applications to stellar triples and extrasolar planets are discussed.
Fragmentation of colliding planetesimals with water content
Authors: Maindl Thomas I. , Dvorak Rudolf , Schäfer Christoph , Speith Roland
Published: January 2015

We investigate the outcome of collisions of Ceres-sized planetesimals composed of a rocky core and a shell of water ice. These collisions are not only relevant for explaining the formation of planetary embryos in early planetary systems, but also provide insight into the formation of asteroid families and possible water transport via colliding small bodies. Earlier studies show characteristic collision velocities exceeding the bodies' mutual escape velocity which—along with the distribution of the impact angles—cover the collision outcome regimes ‘partial accretion’, ‘erosion’, and ‘hit-and-run’ leading to different expected fragmentation scenarios. Existing collision simulations use bodies composed of strengthless material; we study the distribution of fragments and their water contents considering the full elasto-plastic continuum mechanics equations also including brittle failure and fragmentation.
Determination of an Intermediate Perturbed Orbit using Multiple Observations
Authors: Shefer Vladimir A.
Published: January 2015

Two methods are briefly stated for finding the preliminary orbit of a small celestial body from its three or more pairs of angular measurements and the corresponding time instants. The methods are based on using the approach that we previously developed for constructing the intermediate orbit from a minimum number of observations. This intermediate orbit allows for most of the perturbations in the motion of the body under study. The methods proposed use the Herget's algorithmic scheme that makes it possible to involve additional observations as well. Using the determination of orbits of some asteroids as examples, we compare the results obtained by applying the Herget multiple-observation algorithm and the proposed methods. The comparison shows that the proposed methods are an efficient means for studying perturbed motion. They are especially advantageous if applied to high-precision observational data covering short orbital arcs.
Dynamical evolution of objects on highly elliptical orbits near high-order resonance zones
Authors: Kuznetsov Eduard D. , Kudryavtsev Stanislav O.
Published: January 2015

Both analytical and numerical results are used to study high-order resonance regions in the vicinity of Molnya-type orbits. Based on data of numerical simulations, long-term orbital evolution are studied for objects in highly elliptical orbits depending on their area-to-mass ratio. The Poynting–Robertson effect causes a secular decrease in the semi-major axis of a spherically symmetrical satellite. Under the Poynting–Robertson effect, objects pass through the regions of high-order resonances. The Poynting–Robertson effect and secular perturbations of the semi-major axis lead to the formation of weak stochastic trajectories.
The Grand Tack model: a critical review
Authors: Raymond Sean N. , Morbidelli Alessandro
Published: January 2015

The “Grand Tack” model proposes that the inner Solar System was sculpted by the giant planets' orbital migration in the gaseous protoplanetary disk. Jupiter first migrated inward then Jupiter and Saturn migrated back outward together. If Jupiter's turnaround or “tack” point was at ~ 1.5 AU the inner disk of terrestrial building blocks would have been truncated at ~ 1 AU, naturally producing the terrestrial planets' masses and spacing. During the gas giants' migration the asteroid belt is severely depleted but repopulated by distinct planetesimal reservoirs that can be associated with the present-day S and C types. The giant planets' orbits are consistent with the later evolution of the outer Solar System.

Here we confront common criticisms of the Grand Tack model. We show that some uncertainties remain regarding the Tack mechanism itself; the most critical unknown is the timing and rate of gas accretion onto Saturn and Jupiter. Current isotopic and compositional measurements of Solar System bodies – including the D/H ratios of Saturn's satellites – do not refute the model. We discuss how alternate models for the formation of the terrestrial planets each suffer from an internal inconsistency and/or place a strong and very specific requirement on the properties of the protoplanetary disk.

We conclude that the Grand Tack model remains viable and consistent with our current understanding of planet formation. Nonetheless, we encourage additional tests of the Grand Tack as well as the construction of alternate models.
Reversing Type I Migration in Gap Shadows
Authors: Jang-Condell Hannah
Published: January 2015

Type I migration refers to the radial drift of a sub-Jupiter mass planet resulting from tidal interactions with a protoplanetary disk. It results in the rapid inward migration of small planets and planet cores through the disk. Type I migration is so rapid compared to disk dissipation time scales that explaining distant planets, such as the HR 8799 planets and Jupiter itself, is problematic because their growing cores should have been lost. Here, we present a scenario for solving the Type I migration problem. As a planet grows in mass, its Type I migration rate should increase, assuming that disk properties are not significantly altered by the forming planet. But a growing planet clears some, but not all, material from its orbital path, creating a partial gap in the disk. The trough of a partially cleared gap such as this is shadowed from stellar illumination while the far side of the gap is illuminated. Since stellar irradiation is the primary heat source of passively accreting protoplanetary disks, gap self-shadowing can significantly change the local temperature profile. This change to the local temperature gradient can significantly slow, or even reverse Type I migration.
Planet Formation in Close Binaries
Authors: Jang-Condell Hannah
Published: January 2015

Several exoplanets have been discovered in close binaries (a < 30 AU) to date.

The fact that planets can form in these dynamically challenging environments says that planet formation must be a robust process. Disks in these systems should be tidally truncated to within a few AU, so if they form in situ, the efficiency of planet formation must be high. While the dynamical capture of planets is also a possibility, the probability of these interactions is low, so in situ formation is the more plausible explanation. I examine the truncation of protoplanetary disks in close binary stars, studying how the disk mass is affected as it evolves from higher accretion rates to lower rates. In the gamma Cephei system, a protoplanetary disk around the primary star should be truncated to within a few AU, but enough mass still remains for planets to form. However, if the semimajor axis of the binary is too small or its eccentricity is too high, such as in HD 188753, the disk will have too little mass for planet formation to occur. I present a way to characterize the feasibility of planet formation based on binary orbital parameters such as stellar mass, companion mass, eccentricity and semi-major axis. Using this measure, we can quantify the robustness of planet formation in close binaries and better understand the overall efficiency of planet formation in general.
PEOPLE WITH COMMON PRIORS CAN AGREE TO DISAGREE
Authors: LEDERMAN HARVEY
Published: January 2015

Robert Aumann presents hisAgreement Theoremas thekey conditional: “if two people have the same priors and their posteriors for an eventAare common knowledge, then these posteriors are equal” (Aumann, 1976, p. 1236). This paper focuses on four assumptions which are used in Aumann’s proof but are not explicit in the key conditional: (1) that agents commonly know, of some priorμ, that it is the common prior; (2) that agents commonly know that each of them updates on the prior by conditionalization; (3) that agents commonly know that if an agent knows a proposition, she knows that she knows that proposition (the “KK” principle); (4) that agents commonly know that they each update only on true propositions. It is shown that natural weakenings of any one of these strong assumptions can lead to countermodels to Aumann’s key conditional. Examples are given in which agents who have a common prior and commonly know what probability they each assign to a proposition nevertheless assign that proposition unequal probabilities. To alter Aumann’s famous slogan: peoplecan“agree to disagree”, even if they share a common prior. The epistemological significance of these examples is presented in terms of their role in a defense of theUniqueness Thesis: If an agent whose total evidence isEis fully rational in taking doxastic attitudeDtoP, then necessarily, any subject with total evidenceEwho takes a different attitude toPis less than fully rational.
High-sensitivity strain sensor based on in-fiber rectangular air bubble
Authors: Liu Shen , Yang Kaiming , Wang Yiping , Qu Junle , Liao Changrui , He Jun , Li Zhengyong , Yin Guolu , Sun Bing , Zhou Jiangtao , Wang Guanjun , Tang Jian , Zhao Jing
Published: January 2015

We demonstrated a unique rectangular air bubble by means of splicing two sections of standard single mode fibers together and tapering the splicing joint. Such an air bubble can be used to develop a promising high-sensitivity strain sensor based on Fabry-Perot interference. The sensitivity of the strain sensor with a cavity length of about 61 μm and a wall thickness of about 1 μm was measured to be up to 43.0 pm/με and is the highest strain sensitivity among the in-fiber FPI-based strain sensors with air cavities reported so far. Moreover, our strain sensor has a very low temperature sensitivity of about 2.0 pm/°C. Thus, the temperature-induced strain measurement error is less than 0.046 με/°C.
Spectral characterization of postage stamp printing inks by means of Raman spectroscopy
Authors: Imperio Eleonora , Giancane Gabriele , Valli Ludovico
Published: January 2015

A completely non-destructive analysis has been achieved using an ATR-FTIR spectrometer and the filtered laser beam, focalized by the Raman microscope objective lens.
Recurrence prediction in oral cancers: a serum Raman spectroscopy study
Authors: Sahu Aditi , Nandakumar Nikhila , Sawant Sharada , Krishna C. Murali
Published: January 2015

Serum Raman spectroscopy was explored for prediction of oral cancer recurrence in before surgery and after surgery blood samples. Findings suggest RS of post-surgery samples may help in prediction of recurrence.
Identification of spectral biomarkers for type 1 diabetes mellitus using the combination of chiroptical and vibrational spectroscopy
Authors: Šťovíčková Lucie , Tatarkovič Michal , Logerová Hana , Vavřinec Jan , Setnička Vladimír
Published: January 2015

Chiroptical spectroscopy is able to detect conformational changes of plasmatic biomolecules during type 1 diabetes mellitus.
Loss of the preferential control over the striato-nigral direct pathway by striatal NMDA receptors in a rat model of Parkinson's disease
Authors: Morari Michele , Fantin Martina
Published: January 2015

Changes in the striatal NMDA receptor-mediated control over striatofugal pathways in Parkinson's disease, as revealed by dual-probe microdialysis.