Farmer's lung in Ireland (1983-1996) remains at a constant level.
LENUS (Irish Health Repository)
McGrath, D S
2012-02-03
A prospective study was undertaken by the Departments of Respiratory Medicine and Medical Microbiology at the Cork University Hospital, a. to investigate the epidemiology of Farmer\\'s Lung (F.L.) in the Republic of Ireland (pop. 3.5 million), with special reference to the South Western Region of this country (pop. 536,000) and b. to assess any relationship between the prevalence\\/incidence of F.L. with climatic factors in South West Ireland, between 1983 and 1996. F.L. incidence remained constant throughout the 13 yrs studied both on a national and a regional basis. A significant relationship was also found between total rainfall each summer and F.L. incidence and prevalence over the following yr (p < 0.005) in South-West Ireland. The persistence of F.L. in Ireland at a constant level suggests that farmers\\' working environment and farm practices need to be improved.
Directory of Open Access Journals (Sweden)
Philip Verdonck
Full Text Available During robot assisted laparoscopic radical prostatectomy (RALRP, a CO2 pneumoperitoneum (CO2PP is applied and the patient is placed in a head-down position. Intracranial pressure (ICP is expected to acutely increase under these conditions. A non-invasive method, the optic nerve sheath diameter (ONSD measurement, may warn us that the mechanism of protective cerebrospinal fluid (CSF shifts becomes exhausted.After obtaining IRB approval and written informed consent, ONSD was measured by ocular ultrasound in 20 ASA I-II patients at various stages of the RALRP procedure: baseline awake, after induction, after applying the CO2PP, during head-down position, after resuming the supine position, in the postoperative anaesthesia care unit, and on day one postoperatively. Cerebral perfusion pressure (CPP was calculated as the mean arterial (MAP minus central venous pressure (CVP.The ONSD did not change during head-down position, although the CVP increased from 4.2(2.5 mm Hg to 27.6(3.8 mm Hg. The CPP was decreased 70 min after assuming the head-down position until 15 min after resuming the supine position, but remained above 60 mm Hg at all times.Even though ICP has been documented to increase during CO2PP and head-down positioning, we did not find any changes in ONSD during head-down position. These results indicate that intracranial blood volume does not increase up to a point that CSF migration as a compensation mechanism becomes exhausted, suggesting any increases in ICP are likely to be small.
Levels of acute phase proteins remain stable after ischemic stroke
Directory of Open Access Journals (Sweden)
Paik Myunghee C
2006-10-01
Full Text Available Abstract Background Inflammation and inflammatory biomarkers play an important role in atherosclerosis and cardiovascular disease. Little information is available, however, on time course of serum markers of inflammation after stroke. Methods First ischemic stroke patients ≥40 years old had levels of high-sensitivity C-reactive protein (hsCRP, serum amyloid A (SAA, and fibrinogen measured in plasma samples drawn at 1, 2, 3, 7, 14, 21 and 28 days after stroke. Levels were log-transformed as needed, and parametric and non-parametric statistical tests were used to test for evidence of a trend in levels over time. Levels of hsCRP and SAA were also compared with levels in a comparable population of stroke-free participants. Results Mean age of participants with repeated measures (n = 21 was 65.6 ± 11.6 years, and 13 (61.9% were men, and 15 (71.4% were Hispanic. Approximately 75% of patients (n = 15 had mild strokes (NIH Stroke Scale score 0–5. There was no evidence of a time trend in levels of hsCRP, SAA, or fibrinogen for any of the markers during the 28 days of follow-up. Mean log(hsCRP was 1.67 ± 1.07 mg/L (median hsCRP 6.48 mg/L among stroke participants and 1.00 ± 1.18 mg/L (median 2.82 mg/L in a group of 1176 randomly selected stroke-free participants from the same community (p = 0.0252. Conclusion Levels of hsCRP are higher in stroke patients than in stroke-free subjects. Levels of inflammatory biomarkers associated with atherosclerosis, including hsCRP, appear to be stable for at least 28 days after first ischemic stroke.
Yang, Mingyuan; Yang, Changwei; Chen, Ziqiang; Wei, Xianzhao; Chen, Yuanyuan; Zhao, Jian; Shao, Jie; Zhu, Xiaodong; Li, Ming
2016-03-01
A retrospective study. To explore the relationship between the change of lumbar lordosis (LL) and thoracic kyphosis (TK) in AIS patients after correction surgery. TK tends to decrease in Lenke 1 and Lenke 2 AIS patients after correction surgery using pedicle screws, with the compensation of LL decrease. We hypothesize that lumbar lordosis minus thoracic kyphosis (LL-TK) remains constant after correction surgery to achieve the sagittal balance in AIS patients. Medical records of Lenke 1 or Lenke 2 AIS patients who received posterior correction surgery using pedicle screws in our hospital from January 2010 to January 2013 were reviewed. General characters of patients and radiological parameters were evaluated before the surgery and at two years' follow-up. Correlation analysis between TK and LL was conducted. LL-TK and the change of LL and TK were analyzed at preoperation and final follow-up. A total of 76 Lenke 1 and Lenke 2 AIS patients were included. Both TK and LL decreased significantly after correction surgery (P = 0.019 and P = 0.040, respectively). There were significant correlations between TK and LL before and after surgery, respectively (preoperative: r = 0.234, P = 0.042; postoperative: r = 0.310, P = 0.006). Preoperative and postoperative LL-TK was 23.80° and 25.09°, respectively, and no significant difference of LL-TK was observed (P = 0.372). The same tendency was observed in the change of LL and TK, and significant correlation was also found between the change of TK and LL (r = 0.626, P = 0.002). The same change of LL and TK and no significant difference in LL-TK indicated that LL-TK might be an important compensatory mechanism in keeping sagittal balance.
International Nuclear Information System (INIS)
Kaptanoglu, S.
1983-01-01
A class of local gauge theories based on compact semisimple Lie groups is studied in the limit of infinite gauge coupling constant (g = infinity). In general, in this limit, the gauge fields become auxiliary in all gauge theories, and the system develops a richer structure of constraints. Unfortunately for most gauge theories, this limit turns out to be too singular to quantize and the theory ceases to be renormalizable. For a special class of gauge theories, however, where there are no fermions and there is only one multiplet of scalars in the adjoint representation, we prove that a consistent renormalizable quantum theory exists even in this very singular limit. We trace this exceptional behavior to a new local translationlike symmetry in the functional space that this class of gauge models possesses in the limit of infinite gauge coupling constant. By carrying out the constraint analysis, evaluating the Faddeev-Popov-Senjanovic determinant, and doing the functional integrations over the canonical momenta, the gauge fields, and most of the components of the scalar fields, we obtain an extremely simple result with no non-Abelian structure left in it. For example, for the group SU(2), the final answer reduces to the theory of a one-component self-interacting real phi 4 scalar field theory. Throughout this paper, we use functional methods and make no approximations; our results are nonperturbative and exact. We also discuss some of the possible implications of our results
The Remaining Service Time Upon Reaching a High Level in M/G/1 Queues
de Boer, Pieter-Tjerk; Nicola, V.F.; van Ommeren, Jan C.W.
The distribution of the remaining service time upon reaching some target level in an M/G/1 queue is of theoretical as well as practical interest. In general, this distribution depends on the initial level as well as on the target level, say, B. Two initial levels are of particular interest, namely,
Muntaner, Caries; Rai, Nanky; Ng, Edwin; Chung, Haejoo
2012-01-01
Richard Wilkinson and Kate Pickett's latest book, The Spirit Level: Why Equality is Best for Everyone, has caught the attention of academics and policymakers and stimulated debate across the left-right political spectrum. Interest in income inequality has remained unabated since the publication of Wilkinson's previous volume, Unhealthy Societies: The Afflictions of Inequality. While both books detail the negative health effects of income inequality, The Spirit Level expands the scope of its argument to also include social issues. The book, however, deals extensively with the explanation of how income inequality affects individual health. Little attention is given to political and economic explanations on how income inequality is generated in the first place. The volume ends with political solutions that carefully avoid state interventions such as limiting the private sector's role in the production of goods and services (e.g., non-profit sector, employee-ownership schemes). Although well-intentioned, these alternatives are insufficient to significantly reduce the health inequalities generated by contemporary capitalism in wealthy countries, let alone around the world.
40 CFR 57.302 - Performance level of interim constant controls.
2010-07-01
... correction of the effects of any serious deficiencies in the system. For the purpose of this paragraph, at... system if the smelter owner has not upgraded serious deficiencies in the constant control system in... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Performance level of interim constant...
International Nuclear Information System (INIS)
Blauvelt, Richard; Small, Ken; Gelles, Christine; McKenney, Dale; Franz, Bill; Loveland, Kaylin; Lauer, Mike
2006-01-01
Faced with closure schedules as a driving force, significant progress has been made during the last 2 years on the disposition of DOE mixed waste streams thought previously to be problematic. Generators, the Department of Energy and commercial vendors have combined to develop unique disposition paths for former orphan streams. Recent successes and remaining issues will be discussed. The session will also provide an opportunity for Federal agencies to share lessons learned on low- level and mixed low-level waste challenges and identify opportunities for future collaboration. This panel discussion was organized by PAC member Dick Blauvelt, Navarro Research and Engineering Inc who served as co-chair along with Dave Eaton from INL. In addition, George Antonucci, Duratek Barnwell and Rich Conley, AFSC were invited members of the audience, prepared to contribute the Barnwell and DOD perspective to the issues as needed. Mr. Small provide information regarding the five year 20K M3 window of opportunity at the Nevada Test Site for DOE contractors to dispose of mixed waste that cannot be received at the Energy Solutions (Envirocare) site in Utah because of activity levels. He provided a summary of the waste acceptance criteria and the process sites must follow to be certified to ship. When the volume limit or time limit is met, the site will undergo a RCRA closure. Ms. Gelles summarized the status of the orphan issues, commercial options and the impact of the EM reorganization on her program. She also announced that there would be a follow-on meeting in 2006 to the very successful St. Louis meeting of last year. It will probably take place in Chicago in July. Details to be announced. Mr. McKenney discussed progress made at the Hanford Reservation regarding disposal of their mixed waste inventory. The news is good for the Hanford site but not good for the rest of the DOE complex since shipment for out of state of both low level and low level mixed waste will continue to be
International Nuclear Information System (INIS)
Yarman, T.; Kiyak, N.
1991-01-01
This work is based on a previous observation and on a related mathematical modeling regarding the ‘linear growth’ of a colony of microorganisms under given conditions. We had previously shown that the growth rate of the colony is merely proportional to the ‘individual exponential multiplication constant’, β, of the microorganisms. Tiny colonies of penicillium are subjected to different doses of irradiation. The subsequent observation of the colonies' growth rate beautifully furnishes a measure of how the multiplication constant, β, of the microorganism is affected by irradiation. The plot of β with respect to the irradiation dose, shows a linear interdependence between the two quantities. The extrapolation of this plot easily yields the radiation pasteurization dose of the microorganisms in hand
Directory of Open Access Journals (Sweden)
Laura Sommer Hansen
2015-01-01
Full Text Available Introduction: European system for cardiac operative risk evaluation (EuroSCORE is a valuable tool in control of the quality of cardiac surgery. However, the validity of the risk score for the individual patient may be questioned. The present study was carried out to investigate whether the continued fall in short-term mortality reflects an actual improvement in late mortality, and subsequently, to investigate EuroSCORE as predictor of 1-year mortality. Methods: A population-based cohort study of 25,602 patients from a 12-year period from three public university hospitals undergoing coronary artery bypass grafting (CABG or valve surgery. Analysis was carried out based on EuroSCORE, age and co-morbidity factors (residual EuroSCORE. Results: During the period the average age increased from 65.1 ± 10.0 years to 68.9 ± 10.7 years (P < 0.001, one-way ANOVA, and the number of females increased from 26.0% to 28.2% (P = 0.0012, Chi-square test. The total EuroSCORE increased from 4.67 to 5.68 while the residual EuroSCORE decreased from 2.64 to 1.83. Thirty-day mortality decreased from 4.07% in 1999-2000 to 2.44% in 2011-2012 (P = 0.0056; Chi-square test, while 1-year mortality was unchanged (6.50% in 1999-2000 vs. 6.25% in 2011-2012 [P = 0.8086; Chi-square test]. Discussion: The study demonstrates that both co-morbidity and age has a great impact on 30-day mortality. However, with time the impact of co-morbidity seems less. Thus, age is more important than co-morbidity in late mortality. The various developments in short and long-term mortality are not readily explained. Conclusion: Although 30-day mortality of CABG and valve surgery patients has decreased during the 12-year period, the 1-year mortality remains the same.
A constant level liquefied gas regulator sensitive to ± 0,2 mm (1960)
International Nuclear Information System (INIS)
Moreau, C.
1960-01-01
This device has been designed to maintain a constant level of liquid nitrogen around an adsorption bulb used for the determination of specific surface areas by the BET method. We have in fact already shown elsewhere the necessity of defining carefully the temperature in the bulb and of reducing fluctuations to a minimum. Various apparatus has already been described but it did not offer the sensitivity and the safety in use which we have particularly sought to achieve. (author) [fr
Transition probabilities and radiative decay constants of the excited levels of Ne
International Nuclear Information System (INIS)
Wosinski, L.
1981-01-01
Transition probabilities for eight optical transitions between the 3p and 3d neon levels have been measured by the ''plasma transparency method''. The transitions probabilities are placed on an absolute scale by use of the recently reported values for the 4p→3s transitions. The measurements of induced changes in populations allowed the determination of the ratios of the radiative decay constants for the 4p and 3d levels. The experimental results are compared with the theoretically calculated transitions probabilities of Murphy and Lilly. (author)
Constant-resistance deep-level transient spectroscopy in Si and Ge JFET's
International Nuclear Information System (INIS)
Kolev, P.V.; Deen, J.
1999-01-01
The recently introduced constant-resistance deep-level transient spectroscopy (CR-DLTS) was successfully applied to study virgin and radiation-damaged junction field-effect transistors (JFET's). The authors have studied three groups of devices: commercially available-discrete silicon JFET's; virgin and exposed to high-level neutron radiation silicon JFET's, custom-made by using a monolithic technology; and commercially available discrete germanium p-channel JFET's. CR-DLTS is similar to both the conductance DLTs and to the constant-capacitance variation (CC-DLTS). Unlike the conductance and current DLTS, it is independent of the transistor size and does not require simultaneous measurement of the transconductance or the free-carrier mobility for calculation of the trap concentration. Compared to the CC-DLTS, it measures only the traps inside the gate-controlled part of the space charge region. Comparisons have also been made with the CC-DLTS and standard capacitance DLTS. In addition, possibilities for defect profiling in the channel have been demonstrated. CR-DLTS was found to be a simple, very sensitive, and device area-independent technique which is well suited for measurement of a wide range of deep level concentrations in transistors
Ahmed, Ayesha Ejaz; Masood, Komal; Dean, Sohni Vicky; Shakir, Tanzila; Kardar, Ahmed Abdul Hafeez; Barlass, Usman; Imam, Syed Haider; Mohmand, Mohammad Ghawar Khan; Ibrahim, Hussain; Khan, Imad Saeed; Akram, Usman; Hasnain, Farid
2011-04-01
To assess the levels of stress in the face of terrorism and the adopted coping strategies, amongst the student population of universities in Karachi. A descriptive, cross sectional study was conducted on undergraduate students from four universities of Karachi. Self-administered questionnaires were filled out by 291 students. Pearson Chi-Square test was used to assess associations between stress levels and different variables at a level of significance of 0.05%. A total of 65.8% of the students had mild stress levels, 91.5% of university students were exposed to terrorism through television, while only 26.5% students reported personal exposure to terrorism. 67.4% students were forbidden by their parents to go out (p = 0.002). Most of those who had self exposure to an attack were the ones whose parents forbade them from going out (p = 0.00). Most commonly used coping strategy was increased faith in religion. Irritability was the most common stress symptom. A majority of students studying in universities of Karachi had mild stress levels due to the constant threat of terrorism whereas a minority had severe stress levels. Possible reasons for resilience and only mild stress levels could be the history of Karachi's internal conflicts and its prolonged duration of being exposed to terrorism. These students who are positive for stress need to be targeted for counseling either through the media or through their universities. More extensive research is needed in this area.
International Nuclear Information System (INIS)
Valencia, J.; Zarco, L.; Ducoing, A.; Murcia, C.; Navarro, H.
1990-01-01
The objective of this work was to characterize the anoestrous season of Criollo and Granadina goats kept on a constant nutritional level to determine the time of year when ovarian activity ceases, the duration and depth of anoestrus, and the time at which these animals start cycling again. A sample of 19 Criollo and 11 Granadina goats were fed oat hay, concentrate and mineral salts to cover 100% of their nutritional requirements. All animals were adult, non-pregnant and non-lactating and were kept isolated from the males for the duration of the study. Blood samples, taken from all animals twice a week from November 1986 to July 1987 into heparinized tubes, were kept refrigerated until centrifugation for harvest of plasma and then frozen until assayed. Ovarian activity was monitored from the circulating levels of progesterone determined by the FAO/IAEA solid phase radioimmunoassay kit. Concentrations above 1 ng/mL were considered indicative of the presence of a functional corpus luteum and reproductive activity. The majority of the Criollo goats were cycling during November and December, ovarian activity decreasing gradually during February; from March to May most of the goats ceased to ovulate but ovarian activity resumed again in June or July; thus anoestrus was only evident during the spring. In contrast, Granadina goats had a longer and deeper anoestrus; 54% of these animals never showed significant increases in progesterone above basal levels during the period under study (November to July). The short anoestrous season of the Criollo goats and the weak inhibition of ovarian activity during this period suggest that these animals have a greater reproductive potential than the Granadina goats. (author). 21 refs, 7 figs
Gryb, Sean; Thebault, Karim
2014-01-01
On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute 'problem of time'. Under our view, duration is still regarded as relative, but te...
DEFF Research Database (Denmark)
Rusakov, Yury Yu; Krivdin, Leonid B.; Østerstrøm, Freja From
2013-01-01
This paper documents a very first example of a high-level correlated calculation of spin-spin coupling constants involving tellurium taking into account relativistic effects, vibrational corrections and solvent effects for the medium sized organotellurium molecules. The 125Te-1H spin-spin coupling...... constants of tellurophene and divinyl telluride were calculated at the SOPPA and DFT levels in a good agreement with experiment. A new full-electron basis set av3z-J for tellurium derived from the "relativistic" Dyall's basis set, dyall.av3z, and specifically optimized for the correlated calculations...... of spin-spin coupling constants involving tellurium, was developed. The SOPPA methods show much better performance as compared to 15 those of DFT, if relativistic effects calculated within the ZORA scheme are taken into account. Vibrational and solvent corrections are next to negligible, while...
Directory of Open Access Journals (Sweden)
Aydın Pekel
2017-10-01
Full Text Available Background/Objective: Super amateur cluster is examination of the relationship between “self-efficiency” and competence levels and constant sportive self-respect levels of football players. Methods: Population of the study consists of 80 super amateur cluster football clubs operating in European Side of İstanbul Province, and sample of the study consists of (n=310 volunteer football players playing football in 21 sports clubs determined with simple random method. Questionnaire method was applied as data collection tool. The participants were applied personal information form, Self Efficiency Competence Scale which was developed by Sherer and colleagues in 1982 and adapted to Turkish by Gözüm and Aksayan in 1999 and Constant Sportive Self-Respect Scale which was developed by Vealey in 1986 and of which validity and reliability studies were conducted by Yıldırım in 2013. The obtained data was recorded with the package program named "IBM SPSS 22". Correlation analysis and regression analysis were applied as statistical procedure. Results: It was seen that “self-efficiency” and - competence levels of amateur football players were in a good level and constant sportive self-respect levels were high. It was detected that there is a high-level positive relationship between constant sportive self-respect level and “self-efficiency” and -competence level, and that “self-efficiency” and - competence level predicted constant sportive self-respect level. Conclusion: It may be considered that sufficient performance of the football players results from self-completion, motivation, belief in themselves and desire to act for success by using their skills.
A novel frame-level constant-distortion bit allocation for smooth H.264/AVC video quality
Liu, Li; Zhuang, Xinhua
2009-01-01
It is known that quality fluctuation has a major negative effect on visual perception. In previous work, we introduced a constant-distortion bit allocation method [1] for H.263+ encoder. However, the method in [1] can not be adapted to the newest H.264/AVC encoder directly as the well-known chicken-egg dilemma resulted from the rate-distortion optimization (RDO) decision process. To solve this problem, we propose a new two stage constant-distortion bit allocation (CDBA) algorithm with enhanced rate control for H.264/AVC encoder. In stage-1, the algorithm performs RD optimization process with a constant quantization QP. Based on prediction residual signals from stage-1 and target distortion for smooth video quality purpose, the frame-level bit target is allocated by using a close-form approximations of ratedistortion relationship similar to [1], and a fast stage-2 encoding process is performed with enhanced basic unit rate control. Experimental results show that, compared with original rate control algorithm provided by H.264/AVC reference software JM12.1, the proposed constant-distortion frame-level bit allocation scheme reduces quality fluctuation and delivers much smoother PSNR on all testing sequences.
International Nuclear Information System (INIS)
De Cezaro, A; Leitão, A; Tai, X-C
2013-01-01
We investigate level-set-type methods for solving ill-posed problems with discontinuous (piecewise constant) coefficients. The goal is to identify the level sets as well as the level values of an unknown parameter function on a model described by a nonlinear ill-posed operator equation. The PCLS approach is used here to parametrize the solution of a given operator equation in terms of a L 2 level-set function, i.e. the level-set function itself is assumed to be a piecewise constant function. Two distinct methods are proposed for computing stable solutions of the resulting ill-posed problem: the first is based on Tikhonov regularization, while the second is based on the augmented Lagrangian approach with total variation penalization. Classical regularization results (Engl H W et al 1996 Mathematics and its Applications (Dordrecht: Kluwer)) are derived for the Tikhonov method. On the other hand, for the augmented Lagrangian method, we succeed in proving the existence of (generalized) Lagrangian multipliers in the sense of (Rockafellar R T and Wets R J-B 1998 Grundlehren der Mathematischen Wissenschaften (Berlin: Springer)). Numerical experiments are performed for a 2D inverse potential problem (Hettlich F and Rundell W 1996 Inverse Problems 12 251–66), demonstrating the capabilities of both methods for solving this ill-posed problem in a stable way (complicated inclusions are recovered without any a priori geometrical information on the unknown parameter). (paper)
Energy Technology Data Exchange (ETDEWEB)
Harrington, B J; Shepard, H K [New Hampshire Univ., Durham (USA). Dept. of Physics
1976-03-22
By fully exploiting the mathematical and physical analogy to the Ginzburg-Landau theory of superconductivity, a complete discussion of the ground state behavior of the four-dimensional Abelian Higgs model in the static tree level approximation is presented. It is shown that a sufficiently strong external magnetic field can alter the ground state of the theory by restoring a spontaneously broken symmetry, or by creating a qualitatively different 'vortex' state. The energetically favored ground state is explicitly determined as a function of the external field and the ratio between coupling constants of the theory.
Zhang, Zhengfang; Chen, Weifeng
2018-05-01
Maximization of the smallest eigenfrequency of the linearized elasticity system with area constraint is investigated. The elasticity system is extended into a large background domain, but the void is vacuum and not filled with ersatz material. The piecewise constant level set (PCLS) method is applied to present two regions, the original material region and the void region. A quadratic PCLS function is proposed to represent the characteristic function. Consequently, the functional derivative of the smallest eigenfrequency with respect to PCLS function takes nonzero value in the original material region and zero in the void region. A penalty gradient algorithm is proposed, which initializes the whole background domain with the original material and decreases the area of original material region till the area constraint is satisfied. 2D and 3D numerical examples are presented, illustrating the validity of the proposed algorithm.
Kim, Jong In; Kim, Gukbin
2016-10-01
The remaining years of healthy life expectancy (RYH) at age 65 years can be calculated as RYH (65) = healthy life expectancy-aged 65 years. This study confirms the associations between socioeconomic indicators and the RYH (65) in 148 countries. The RYH data were obtained from the World Health Organization. Significant positive correlations between RYH (65) in men and women and the socioeconomic indicators national income, education level, and improved drinking water were found. Finally, the predictors of RYH (65) in men and women were used to build a model of the RYH using higher socioeconomic indicators (R(2 )= 0.744, p educational attainment, national income level, and improved water quality influenced the RYH at 65 years. Therefore, policymaking to improve these country-level socioeconomic factors is expected to have latent effects on RYH in older age. © The Author(s) 2016.
International Nuclear Information System (INIS)
Tavassoly, M.K.; Hekmatara, H.
2015-01-01
In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system. (paper)
Energy Technology Data Exchange (ETDEWEB)
Wang, De-Gao, E-mail: degaowang@dlmu.edu.cn; Du, Juan; Pei, Wei; Liu, Yongjun; Guo, Mingxing
2015-04-15
The fate of cyclic and linear volatile methylsiloxanes (VMSs) was evaluated in a wastewater treatment plant (WWTP) using constant water level sequencing batch reactors from Dalian, China. Influent, effluent, and sewage sludge samples were collected for seven consecutive days. The mean concentrations of cyclic VMSs (cVMSs) in influent and effluent samples are 1.05 μg L{sup −1} and 0.343 μg L{sup −1}; the total removal efficiency of VMSs is > 60%. Linear VMS (lVMS) concentration is under the quantification limitation in aquatic samples but is found in sludge samples with a value of 90 μg kg{sup −1}. High solid-water partition coefficients result in high VMS concentrations in sludge with the mean value of 5030 μg kg{sup −1}. No significant differences of the daily mass flows are found when comparing the concentration during the weekend and during working days. The estimated mass load of total cVMSs is 194 mg d{sup −1} 1000 inhabitants{sup −1} derived for the population. A mass balance model of the WWTP was developed and derived to simulate the fate of cVMSs. The removal by sorption on sludge increases, and the volatilization decreases with increasing hydrophobicity and decreasing volatility for cVMSs. Sensitivity analysis shows that the total suspended solid concentration in the effluent, mixed liquor suspended solid concentration, the sewage sludge flow rate, and the influent flow rate are the most influential parameters on the mass distribution of cVMSs in this WWTP. - Highlights: • A mass balance model for siloxanes was developed in sequencing batch reactor. • Total suspended solid in effluent has the most influence on removal efficiency. • Enhancement of suspended solid removal reduces the release to aquatic environment.
Indian Academy of Sciences (India)
IAS Admin
The article discusses the importance of the fine structure constant in quantum mechanics, along with the brief history of how it emerged. Al- though Sommerfelds idea of elliptical orbits has been replaced by wave mechanics, the fine struc- ture constant he introduced has remained as an important parameter in the field of ...
International Nuclear Information System (INIS)
Foos, J.
1999-01-01
This paper is written in two tables. The first one describes the different particles (bosons and fermions). The second one gives the isotopes nuclear constants of the different elements, for Z = 1 to 56. (A.L.B.)
International Nuclear Information System (INIS)
Foos, J.
2000-01-01
This paper is written in two tables. The first one describes the different particles (bosons and fermions). The second one gives the isotopes nuclear constants of the different elements, for Z = 56 to 68. (A.L.B.)
International Nuclear Information System (INIS)
Foos, J.
1998-01-01
This paper is made of two tables. The first table describes the different particles (bosons and fermions) while the second one gives the nuclear constants of isotopes from the different elements with Z = 1 to 25. (J.S.)
International Nuclear Information System (INIS)
Foos, J.
1999-01-01
This paper is written in two tables. The first one describes the different particles (bosons and fermions). The second one gives the isotopes nuclear constants of the different elements, for Z = 56 to 68. (A.L.B.)
Are fundamental constants really constant
International Nuclear Information System (INIS)
Norman, E.B.
1986-01-01
Reasons for suspecting that fundamental constants might change with time are reviewed. Possible consequences of such variations are examined. The present status of experimental tests of these ideas is discussed
Raboh, Ghada
2018-01-01
A high performance liquid chromatography (HPLC) experiment for the upper level analytical chemistry laboratory is described. The students consider the effect of mobile-phase composition and pH on the retention times of ionizable compounds in order to determine the acid dissociation constant, K[subscript a], of a phenolic acid. Results are analyzed…
Maciejczyk, Marcin; Więcek, M; Szymura, J; Szyguła, Z
2013-09-01
The purpose of this study was to compare the physiological and the acid-base balance response to running at various slope angles. Ten healthy men 22.3 ± 1.56 years old participated in the study. The study consisted of completing the graded test until exhaustion and three 45-minute runs. For the first 30 minutes, runs were performed with an intensity of approximately 50% VO2max, while in the final 15 minutes the slope angle of treadmill was adjusted (0°; +4.5°; -4.5°), and a fixed velocity of running was maintained. During concentric exercise, a significant increase in the levels of physiological indicators was reported; during eccentric exercise, a significant decrease in the level of the analyzed indicators was observed. Level running did not cause significant changes in the indicators of acid-base balance. The indicators of acid-base balance changed significantly in the case of concentric muscle work (in comparison to level running) and after the eccentric work, significant and beneficial changes were observed in most of the biochemical indicators. The downhill run can be used for a partial regeneration of the body during exercise, because during this kind of effort an improvement of running economy was observed, and this type of effort did not impair the acid-base balance of body.
Directory of Open Access Journals (Sweden)
Matthew S Freiberg
Full Text Available The mechanism underlying the excess risk of non-AIDS diseases among HIV infected people is unclear. HIV associated inflammation/hypercoagulability likely plays a role. While antiretroviral therapy (ART may return this process to pre-HIV levels, this has not been directly demonstrated. We analyzed data/specimens on 249 HIV+ participants from the US Military HIV Natural History Study, a prospective, multicenter observational cohort of >5600 active duty military personnel and beneficiaries living with HIV. We used stored blood specimens to measure D-dimer and Interleukin-6 (IL-6 at three time points: pre-HIV seroconversion, ≥6 months post-HIV seroconversion but prior to ART initiation, and ≥6 months post-ART with documented HIV viral suppression on two successive evaluations. We evaluated the changes in biomarker levels between time points, and the association between these biomarker changes and future non-AIDS events. During a median follow-up of 3.7 years, there were 28 incident non-AIDS diseases. At ART initiation, the median CD4 count was 361cells/mm3; median duration of documented HIV infection 392 days; median time on ART was 354 days. Adjusted mean percent increase in D-dimer levels from pre-seroconversion to post-ART was 75.1% (95% confidence interval 24.6-148.0, p = 0.002. This increase in D-dimer was associated with a significant 22% increase risk of future non-AIDS events (p = 0.03. Changes in IL-6 levels across time points were small and not associated with future non-AIDS events. In conclusion, ART initiation and HIV viral suppression does not eliminate HIV associated elevation in D-dimer levels. This residual pathology is associated with an increased risk of future non-AIDS diseases.
Kolesniková, Lucie; Koucký, Jan; Kania, Patrik; Uhlíková, Tereza; Beckers, Helmut; Urban, Štěpán
2018-01-01
The resonance crossing of rotational levels with different fine-structure components and different k rotational quantum numbers was observed in the rotational spectra of the symmetric top fluorosulfate radical FSO3rad. Detailed measurements were performed to analyze these weak resonances as well as the A1-A2 splittings of the K = 3 and K = 6 transitions. The resonance level crossing enabled the experimental determination of "forbidden" parameters, the rotational A and the centrifugal distortion DK constants as well as the corresponding resonance off-diagonal matrix element.
Bunker, T W; Koetje, D S; Stephenson, L C; Creelman, R A; Mullet, J E; Grimes, H D
1995-08-01
The response of individual members of the lipoxygenase multigene family in soybeans to sink deprivation was analyzed. RNase protection assays indicated that a novel vegetative lipoxygenase gene, vlxC, and three other vegetative lipoxygenase mRNAs accumulated in mature leaves in response to a variety of sink limitations. These data suggest that several members of the lipoxygenase multigene family are involved in assimilate partitioning. The possible involvement of jasmonic acid as a signaling molecule regulating assimilate partitioning into the vegetative storage proteins and lipoxygenases was directly assessed by determining the endogenous level of jasmonic acid in leaves from plants with their pods removed. There was no rise in the level of endogenous jasmonic acid coincident with the strong increase in both vlxC and vegetative storage protein VspB transcripts in response to sink limitation. Thus, expression of the vegetative lipoxygenases and vegetative storage proteins is not regulated by jasmonic acid in sink-limited leaves.
Energy Technology Data Exchange (ETDEWEB)
Villalba, Victor M.; Pino, Ramiro [Instituto Venezolano de Investigaciones Cientificas, Caracas (Venezuela)
2001-03-01
In this article we review different techniques for computing the energy spectrum of 2 D hydrogenic donors and two-electron quantum dots in the presence of a constant, magnetic field perpendicular to the plane of the electron. We compute the 1S, 2P- and 3D- energy levels via a scaled variational mixed-bases method. We compare our results with those obtained with the shifted 1/N method. [Spanish] En el presente articulo se exhiben distintos metodos para calcular el espectro de energia de donores hidrogenicos y puntos cuanticos con dos electrones en presencia de un campo magnetico constante perpendicular al plano del electron. Se calculan los niveles de energia 1S, 2P- y 3D- con ayuda del metodo variacional de bases mixtas con escalamiento. Comparamos nuestro resultados con los obtenidos con ayuda del metodo 1/N con corrimiento.
Sakai, Kiyoshi; Kamijima, Michihiro; Shibata, Eiji; Ohno, Hiroyuki; Nakajima, Tamie
2010-09-01
This study aimed to clarify indoor air pollution levels of volatile organic compounds (VOCs), especially 2-ethyl-1-hexanol (2E1H) in large buildings after revising of the Act on Maintenance of Sanitation in Buildings in 2002. We measured indoor air VOC concentrations in 57 (97%) out of a total of 61 large buildings completed within one year in half of the area of Nagoya, Japan, from 2003 through 2007. Airborne concentrations of 13 carbonyl compounds were determined with diffusion samplers and high-performance liquid chromatography, and of the other 32 VOCs with diffusion samplers and gas chromatography with a mass spectrometer. Formaldehyde was detected in all samples of indoor air but the concentrations were lower than the indoor air quality standard value set in Japan (100 microg/m3). Geometric mean concentrations of the other major VOCs, namely toluene, xylene, ethylbenzene, styrene, p-dichlorobenzene and acetaldehyde were also low. 2E1H was found to be one of the predominating VOCs in indoor air of large buildings. A few rooms in a small number of buildings surveyed showed high concentrations of 2E1H, while low concentrations were observed in most rooms of those buildings as well as in other buildings. It was estimated that about 310 buildings had high indoor air pollution levels of 2E1H, with increase during the 5 years from 2003 in Japan. Indoor air pollution levels of VOCs in new large buildings are generally good, although a few rooms in a small number of buildings showed high concentrations in 2E1H, a possible causative chemical in sick building symptoms. Therefore, 2E1H needs particular attention as an important indoor air pollutant.
[PALEOPATHOLOGY OF HUMAN REMAINS].
Minozzi, Simona; Fornaciari, Gino
2015-01-01
Many diseases induce alterations in the human skeleton, leaving traces of their presence in ancient remains. Paleopathological examination of human remains not only allows the study of the history and evolution of the disease, but also the reconstruction of health conditions in the past populations. This paper describes the most interesting diseases observed in skeletal samples from the Roman Imperial Age necropoles found in urban and suburban areas of Rome during archaeological excavations in the last decades. The diseases observed were grouped into the following categories: articular diseases, traumas, infections, metabolic or nutritional diseases, congenital diseases and tumours, and some examples are reported for each group. Although extensive epidemiological investigation in ancient skeletal records is impossible, the palaeopathological study allowed to highlight the spread of numerous illnesses, many of which can be related to the life and health conditions of the Roman population.
Basura, G J; Walker, P D
1999-08-05
Sixty days after bilateral dopamine (DA) depletion (>98%) with 6-hydroxydopamine (6-OHDA) in neonatal rats, serotonin (5-HT) content doubled and 5-HT(2A) receptor mRNA expression rose 54% within the rostral striatum. To determine if striatal 5-HT(2A) receptor mRNA upregulation is dependent on increased 5-HT levels following DA depletion, neonatal rats received dual injections of 6-OHDA and 5,7-dihydroxytryptamine (5,7-DHT) which suppressed 5-HT content by approximately 90%. In these 6-OHDA/5,7-DHT-treated rats, striatal 5-HT(2A) receptor mRNA expression was still elevated (87% above vehicle controls). Comparative analysis of 5-HT(2C) receptor mRNA expression yielded no significant changes in any experimental group. These results demonstrate that upregulated 5-HT(2A) receptor biosynthesis in the DA-depleted rat is not dependent on subsequent 5-HT hyperinnervation. Copyright 1999 Elsevier Science B.V.
Hill, Paul T.; Guin, Kacey; Celio, Mary Beth
2003-01-01
Argues that "A Nation at Risk" failed to address adequately problems of urban education, and thus the achievement gap between minority and white students still exists. Describes several problems that still plague low-performing urban schools, such as bureaucratic aversion to change, high levels of poverty, and low teacher quality and…
Energy Technology Data Exchange (ETDEWEB)
Goodman, A L [Tulane Univ., New Orleans, LA (United States)
1992-08-01
Statistical orientation fluctuations are calculated with two alternative assumptions: the rotational frequency remains constant as the shape orientation fluctuates; and, the average angular momentum remains constant as the shape orientation fluctuates. (author). 2 refs., 3 figs.
Wallace, Jason A; Shen, Jana K
2012-11-14
Recent development of constant pH molecular dynamics (CpHMD) methods has offered promise for adding pH-stat in molecular dynamics simulations. However, until now the working pH molecular dynamics (pHMD) implementations are dependent in part or whole on implicit-solvent models. Here we show that proper treatment of long-range electrostatics and maintaining charge neutrality of the system are critical for extending the continuous pHMD framework to the all-atom representation. The former is achieved here by adding forces to titration coordinates due to long-range electrostatics based on the generalized reaction field method, while the latter is made possible by a charge-leveling technique that couples proton titration with simultaneous ionization or neutralization of a co-ion in solution. We test the new method using the pH-replica-exchange CpHMD simulations of a series of aliphatic dicarboxylic acids with varying carbon chain length. The average absolute deviation from the experimental pK(a) values is merely 0.18 units. The results show that accounting for the forces due to extended electrostatics removes the large random noise in propagating titration coordinates, while maintaining charge neutrality of the system improves the accuracy in the calculated electrostatic interaction between ionizable sites. Thus, we believe that the way is paved for realizing pH-controlled all-atom molecular dynamics in the near future.
Directory of Open Access Journals (Sweden)
Neal Jackson
2015-09-01
Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.
Constant physics and characteristics of fundamental constant
International Nuclear Information System (INIS)
Tarrach, R.
1998-01-01
We present some evidence which supports a surprising physical interpretation of the fundamental constants. First, we relate two of them through the renormalization group. This leaves as many fundamental constants as base units. Second, we introduce and a dimensional system of units without fundamental constants. Third, and most important, we find, while interpreting the units of the a dimensional system, that is all cases accessible to experimentation the fundamental constants indicate either discretization at small values or boundedness at large values of the corresponding physical quantity. (Author) 12 refs
Barre, D E; Mizier-Barre, K A; Griscti, O; Hafez, K
2016-10-01
Elevated total serum free fatty acids (FFAs) concentrations have been suggested, controversially, to enhance insulin resistance and decrease percent remaining β-cell function. However, concentrations of individual serum FFAs have never been published in terms of their relationship (correlation) to homeostatic model assessment-insulin resistance (HOMA-IR) and percent remaining β-cell function (HOMA-%β) in the type 2 diabetics (T2Ds). Alpha-linolenic acid consumption has a negative correlation with the insulin resistance, which in turn is negatively correlated with the remaining β-cell function. The primary objective was to test the hypothesis that there would be different relationship (correlation) between the blood serum individual free FFA mol % levels and HOMA-IR and/or HOMA-%β in T2D. The secondary objective was to test the hypothesis that flaxseed oil, previously being shown to be ineffective in the glycemic control in T2Ds, may alter these correlations in a statistically significant manner as well as HOMA-IR and/or HOMA-%β. Patients were recruited via a newspaper advertisement and two physicians have been employed. All the patients came to visit one and three months later for a second visit. At the second visit, the subjects were randomly assigned (double blind) to flaxseed or safflower oil treatment for three months, until the third visit. Different statistically significant correlations or trends towards among some serum individual free FFA mol % levels and HOMA-IR and HOMA-%β, pre- and post-flaxseed and safflower oil supplementation were found. However, flaxseed oil had no impact on HOMA-IR or HOMA-%β despite statistically significant alterations in correlations compared to baseline HOMA-IR. The obtained data indicate that high doses of flaxseed oil have no statistically significant effect on HOMA-IR or HOMA-%β in T2Ds, probably due to the additive effects of negative and positive correlations.
Cosmological Hubble constant and nuclear Hubble constant
International Nuclear Information System (INIS)
Horbuniev, Amelia; Besliu, Calin; Jipa, Alexandru
2005-01-01
The evolution of the Universe after the Big Bang and the evolution of the dense and highly excited nuclear matter formed by relativistic nuclear collisions are investigated and compared. Values of the Hubble constants for cosmological and nuclear processes are obtained. For nucleus-nucleus collisions at high energies the nuclear Hubble constant is obtained in the frame of different models involving the hydrodynamic flow of the nuclear matter. Significant difference in the values of the two Hubble constant - cosmological and nuclear - is observed
FORMATION CONSTANTS AND THERMODYNAMIC ...
African Journals Online (AJOL)
KEY WORDS: Metal complexes, Schiff base ligand, Formation constant, DFT calculation ... best values for the formation constants of the proposed equilibrium model by .... to its positive charge distribution and the ligand deformation geometry.
Ion exchange equilibrium constants
Marcus, Y
2013-01-01
Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and
Energy Technology Data Exchange (ETDEWEB)
Ikeya, T.; Mita, Y.; Iwahori, T. [Central Research Institute of Electric Power Industry, Tokyo (Japan); Iwasaki, M.; Takagi, S.; Sugii, Y.; Yada, M.; Sakabe, T.; Kosaka, E.; Tsuchiya, H.; Kanetsuki, M.; Nasu, H.; Ono, M.; Adachi, K.; Narisoko, H.; Nishiyama, K.
1997-02-01
In the constant-current/constant-voltage charging method that has been in application for EV (electric vehicle) lead-acid batteries, power load is generated only at the initial part of the charging process, and therefore the method cannot be said to be sufficiently contributory to the levelling of power loads. In this report, a proposed 2-step constant-current charging method is assessed for applicability, and another charging method is introduced, which extends battery life and utilizes low-cost night-time power more effectively. It is found that the proposed 2-step constant-current charging method (1st step: 12A, 2nd step: 3A) completes the charging process in eight hours, that it assumes a charging pattern more suitable for contributing to the effective use of night-time power than the conventional method, and that it extends the battery life of approximately 170 cycles to approximately 300 cycles. In a study seeking for a charging method capable of utilizing night-time power more efficiently, the 1st-step current of 12A is increased to 30A for shortening the charging time, and then it is found that this change extends the battery cycle life and improves on charging efficiency. The conclusion is that possibilities are high that an increase in the 1st-step current prolongs the battery life cycle and shortens the charting time. 16 refs., 28 figs., 8 tabs.
Wang, K.; Zhang, C. Y.; Jönsson, P.; Si, R.; Zhao, X. H.; Chen, Z. B.; Guo, X. L.; Chen, C. Y.; Yan, J.
2018-03-01
Employing two state-of-the-art methods, multiconfiguration Dirac-Hartree-Fock and second-order many-body perturbation theory, highly accurate calculations are performed for the lowest 272 fine-structure levels arising from the 2s22p3, 2s2p4, 2p5, 2s22p23l (l = s , p , d), 2s2p33l (l = s , p , d), and 2p43l (l = s , p , d) configurations in nitrogen-like Ge XXVI. Complete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors, and E1, E2, M1, M2 line strengths, oscillator strengths, and transition rates among these 272 levels are provided. Comparisons are made between the present two data sets, as well as with other available experimental and theoretical values. The present data are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing fusion plasmas.
Directory of Open Access Journals (Sweden)
Peter Read
2013-08-01
Full Text Available In most cultures the dead and their living relatives are held in a dialogic relationship. The dead have made it clear, while living, what they expect from their descendants. The living, for their part, wish to honour the tombs of their ancestors; at the least, to keep the graves of the recent dead from disrepair. Despite the strictures, the living can fail their responsibilities, for example, by migration to foreign countries. The peripatetic Chinese are one of the few cultures able to overcome the dilemma of the wanderer or the exile. With the help of a priest, an Australian Chinese migrant may summon the soul of an ancestor from an Asian grave to a Melbourne temple, where the spirit, though removed from its earthly vessel, will rest and remain at peace. Amongst cultures in which such practices are not culturally appropriate, to fail to honour the family dead can be exquisitely painful. Violence is the cause of most failure.
Cosmological constants and variations
International Nuclear Information System (INIS)
Barrow, John D
2005-01-01
We review properties of theories for the variation of the gravitation and fine structure 'constants'. We highlight some general features of the cosmological models that exist in these theories with reference to recent quasar data that is consistent with time-variation in the fine structure 'constant' since a redshift of 3.5. The behaviour of a simple class of varying alpha cosmologies is outlined in the light of all the observational constraints. We also discuss some of the consequences of varying 'constants' for oscillating universes and show by means of exact solutions that they appear to evolve monotonically in time even though the scale factor of the universe oscillates
The cosmological constant problem
International Nuclear Information System (INIS)
Dolgov, A.D.
1989-05-01
A review of the cosmological term problem is presented. Baby universe model and the compensating field model are discussed. The importance of more accurate data on the Hubble constant and the Universe age is stressed. 18 refs
Red Assembly: the work remains
Directory of Open Access Journals (Sweden)
Leslie Witz
installed. What to do at this limit, at the transgressive encounter between saying yes and no to history, remains the challenge. It is the very challenge of what insistently remains.
Green business will remain green
International Nuclear Information System (INIS)
Marcan, P.
2008-01-01
It all started with two words. Climate change. The carbon dioxide trading scheme, which was the politicians' idea on solving the number one global problem, followed. Four years ago, when the project was begun, there was no data for project initiation. Quotas for polluters mainly from energy production and other energy demanding industries were distributed based on spreadsheets, maximum output and expected future development of economies. Slovak companies have had a chance to profit from these arrangements since 2005. Many of them took advantage of the situation and turned the excessive quotas into an extraordinary profit which often reached hundreds of million Sk. The fact that the price of free quotas offered for sale dropped basically to 0 in 2006 only proved that the initial distribution was too generous. And the market reacted to the first official measurements of emissions. Slovak companies also contributed to this development. However, when planning the maximum emission volumes for 2008-2012 period, in spite of the fact that actual data were available, their expectations were not realistic. A glance at the figures in the proposal of the Ministry of Environment is sufficient to realize that there will be no major change in the future. And so for many Slovak companies business with a green future will remain green for the next five years. The state decided to give to selected companies even more free space as far as emissions are concerned. The most privileged companies can expect quotas increased by tens of percent. (author)
Silicon photonics: some remaining challenges
Reed, G. T.; Topley, R.; Khokhar, A. Z.; Thompson, D. J.; Stanković, S.; Reynolds, S.; Chen, X.; Soper, N.; Mitchell, C. J.; Hu, Y.; Shen, L.; Martinez-Jimenez, G.; Healy, N.; Mailis, S.; Peacock, A. C.; Nedeljkovic, M.; Gardes, F. Y.; Soler Penades, J.; Alonso-Ramos, C.; Ortega-Monux, A.; Wanguemert-Perez, G.; Molina-Fernandez, I.; Cheben, P.; Mashanovich, G. Z.
2016-03-01
This paper discusses some of the remaining challenges for silicon photonics, and how we at Southampton University have approached some of them. Despite phenomenal advances in the field of Silicon Photonics, there are a number of areas that still require development. For short to medium reach applications, there is a need to improve the power consumption of photonic circuits such that inter-chip, and perhaps intra-chip applications are viable. This means that yet smaller devices are required as well as thermally stable devices, and multiple wavelength channels. In turn this demands smaller, more efficient modulators, athermal circuits, and improved wavelength division multiplexers. The debate continues as to whether on-chip lasers are necessary for all applications, but an efficient low cost laser would benefit many applications. Multi-layer photonics offers the possibility of increasing the complexity and effectiveness of a given area of chip real estate, but it is a demanding challenge. Low cost packaging (in particular, passive alignment of fibre to waveguide), and effective wafer scale testing strategies, are also essential for mass market applications. Whilst solutions to these challenges would enhance most applications, a derivative technology is emerging, that of Mid Infra-Red (MIR) silicon photonics. This field will build on existing developments, but will require key enhancements to facilitate functionality at longer wavelengths. In common with mainstream silicon photonics, significant developments have been made, but there is still much left to do. Here we summarise some of our recent work towards wafer scale testing, passive alignment, multiplexing, and MIR silicon photonics technology.
Tomsic, Z.; Rajsl, I.; Filipovic, M.
2017-11-01
Wind power varies over time, mainly under the influence of meteorological fluctuations. The variations occur on all time scales. Understanding these variations and their predictability is of key importance for the integration and optimal utilization of wind in the power system. There are two major attributes of variable generation that notably impact the participation on power exchanges: Variability (the output of variable generation changes and resulting in fluctuations in the plant output on all time scales) and Uncertainty (the magnitude and timing of variable generation output is less predictable, wind power output has low levels of predictability). Because of these variability and uncertainty wind plants cannot participate to electricity market, especially to power exchanges. For this purpose, the paper presents techno-economic analysis of work of wind plants together with combined cycle gas turbine (CCGT) plant as support for offering continues power to electricity market. A model of wind farms and CCGT plant was developed in program PLEXOS based on real hourly input data and all characteristics of CCGT with especial analysis of techno-economic characteristics of different types of starts and stops of the plant. The Model analyzes the followings: costs of different start-stop characteristics (hot, warm, cold start-ups and shutdowns) and part load performance of CCGT. Besides the costs, the technical restrictions were considered such as start-up time depending on outage duration, minimum operation time, and minimum load or peaking capability. For calculation purposes, the following parameters are necessary to know in order to be able to economically evaluate changes in the start-up process: ramp up and down rate, time of start time reduction, fuel mass flow during start, electricity production during start, variable cost of start-up process, cost and charges for life time consumption for each start and start type, remuneration during start up time regarding
Radiographic constant exposure technique
DEFF Research Database (Denmark)
Domanus, Joseph Czeslaw
1985-01-01
The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...
International Nuclear Information System (INIS)
Chandra, R.
1977-01-01
On the grounds of the two correspondence limits, the Newtonian limit and the special theory limit of Einstein field equations, a modification of the cosmical constant has been proposed which gives realistic results in the case of a homogeneous universe. Also, according to this modification an explanation for the negative pressure in the steady-state model of the universe has been given. (author)
International Nuclear Information System (INIS)
Weinberg, S.
1989-01-01
Cosmological constant problem is discussed. History of the problem is briefly considered. Five different approaches to solution of the problem are described: supersymmetry, supergravity, superstring; anthropic approach; mechamism of lagrangian alignment; modification of gravitation theory and quantum cosmology. It is noted that approach, based on quantum cosmology is the most promising one
International Nuclear Information System (INIS)
O Murchadha, N.
1991-01-01
The set of riemannian three-metrics with positive Yamabe constant defines the space of independent data for the gravitational field. The boundary of this set is investigated, and it is shown that metrics close to the boundary satisfy the positive-energy theorem. (Author) 18 refs
Constant conditional entropy and related hypotheses
International Nuclear Information System (INIS)
Ferrer-i-Cancho, Ramon; Dębowski, Łukasz; Moscoso del Prado Martín, Fermín
2013-01-01
Constant entropy rate (conditional entropies must remain constant as the sequence length increases) and uniform information density (conditional probabilities must remain constant as the sequence length increases) are two information theoretic principles that are argued to underlie a wide range of linguistic phenomena. Here we revise the predictions of these principles in the light of Hilberg’s law on the scaling of conditional entropy in language and related laws. We show that constant entropy rate (CER) and two interpretations for uniform information density (UID), full UID and strong UID, are inconsistent with these laws. Strong UID implies CER but the reverse is not true. Full UID, a particular case of UID, leads to costly uncorrelated sequences that are totally unrealistic. We conclude that CER and its particular cases are incomplete hypotheses about the scaling of conditional entropies. (letter)
Inflation with a constant rate of roll
International Nuclear Information System (INIS)
Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi
2015-01-01
We consider an inflationary scenario where the rate of inflaton roll defined by ·· φ/H φ-dot remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of 'constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime
Evolution of the solar constant
International Nuclear Information System (INIS)
Newman, M.J.
1978-01-01
The ultimate source of the energy utilized by life on Earth is the Sun, and the behavior of the Sun determines to a large extent the conditions under which life originated and continues to thrive. What can be said about the history of the Sun. Has the solar constant, the rate at which energy is received by the Earth from the Sun per unit area per unit time, been constant at its present level since Archean times. Three mechanisms by which it has been suggested that the solar energy output can vary with time are discussed, characterized by long (approx. 10 9 years), intermediate (approx. 10 8 years), and short (approx. years to decades) time scales
Production in constant evolution
International Nuclear Information System (INIS)
Lozano, T.
2009-01-01
The Cofrentes Nuclear Power Plant now has 25 years of operation behind it: a quarter century adding value and demonstrating the reasons why it is one of the most important energy producing facilities in the Spanish power market. Particularly noteworthy is the enterprising spirit of the plant, which has strived to continuously improve with the large number of modernization projects that it has undertaken over the past 25 years. The plant has constantly evolved thanks to the amount of investments made to improve safety and reliability and the perseverance to stay technologically up to date. Efficiency, training and teamwork have been key to the success of the plant over these 25 years of constant change and progress. (Author)
International Nuclear Information System (INIS)
Blake, J.B.; Dearborn, D.S.P.
1979-01-01
Small fluctuations in the solar constant can occur on timescales much shorter than the Kelvin time. Changes in the ability of convection to transmit energy through the superadiabatic and transition regions of the convection zone cause structure adjustments which can occur on a time scale of days. The bulk of the convection zone reacts to maintain hydrostatic equilibrium (though not thermal equilibrium) and causes a luminosity change. While small radius variations will occur, most of the change will be seen in temperature
Stabilized power constant alimentation
International Nuclear Information System (INIS)
Roussel, L.
1968-06-01
The study and realization of a stabilized power alimentation variable from 5 to 100 watts are described. In order to realize a constant power drift of Lithium compensated diodes, we have searched a 1 per cent precision of regulation and a response time minus than 1 sec. Recent components like Hall multiplicator and integrated amplifiers give this possibility and it is easy to use permutable circuits. (author) [fr
Yongquan, Han
2016-10-01
The ideal gas state equation is not applicable to ordinary gas, it should be applied to the Electromagnetic ``gas'' that is applied to the radiation, the radiation should be the ultimate state of matter changes or initial state, the universe is filled with radiation. That is, the ideal gas equation of state is suitable for the Singular point and the universe. Maybe someone consider that, there is no vessel can accommodate radiation, it is because the Ordinary container is too small to accommodate, if the radius of your container is the distance that Light through an hour, would you still think it can't accommodates radiation? Modern scientific determinate that the radius of the universe now is about 1027 m, assuming that the universe is a sphere whose volume is approximately: V = 4.19 × 1081 cubic meters, the temperature radiation of the universe (cosmic microwave background radiation temperature of the universe, should be the closest the average temperature of the universe) T = 3.15k, radiation pressure P = 5 × 10-6 N / m 2, according to the law of ideal gas state equation, PV / T = constant = 6 × 1075, the value of this constant is the universe, The singular point should also equal to the constant Author: hanyongquan
Connecting Fundamental Constants
International Nuclear Information System (INIS)
Di Mario, D.
2008-01-01
A model for a black hole electron is built from three basic constants only: h, c and G. The result is a description of the electron with its mass and charge. The nature of this black hole seems to fit the properties of the Planck particle and new relationships among basic constants are possible. The time dilation factor in a black hole associated with a variable gravitational field would appear to us as a charge; on the other hand the Planck time is acting as a time gap drastically limiting what we are able to measure and its dimension will appear in some quantities. This is why the Planck time is numerically very close to the gravitational/electric force ratio in an electron: its difference, disregarding a π√(2) factor, is only 0.2%. This is not a coincidence, it is always the same particle and the small difference is between a rotating and a non-rotating particle. The determination of its rotational speed yields accurate numbers for many quantities, including the fine structure constant and the electron magnetic moment
International Nuclear Information System (INIS)
Willson, R.C.; Hudson, H.
1984-01-01
The Active Cavity Radiometer Irradiance Monitor (ACRIM) of the Solar Maximum Mission satellite measures the radiant power emitted by the sun in the direction of the earth and has worked flawlessly since 1980. The main motivation for ACRIM's use to measure the solar constant is the determination of the extent to which this quantity's variations affect earth weather and climate. Data from the solar minimum of 1986-1987 is eagerly anticipated, with a view to the possible presence of a solar cycle variation in addition to that caused directly by sunspots
Cryptography in constant parallel time
Applebaum, Benny
2013-01-01
Locally computable (NC0) functions are 'simple' functions for which every bit of the output can be computed by reading a small number of bits of their input. The study of locally computable cryptography attempts to construct cryptographic functions that achieve this strong notion of simplicity and simultaneously provide a high level of security. Such constructions are highly parallelizable and they can be realized by Boolean circuits of constant depth.This book establishes, for the first time, the possibility of local implementations for many basic cryptographic primitives such as one-way func
Zero cosmological constant from normalized general relativity
International Nuclear Information System (INIS)
Davidson, Aharon; Rubin, Shimon
2009-01-01
Normalizing the Einstein-Hilbert action by the volume functional makes the theory invariant under constant shifts in the Lagrangian. The associated field equations then resemble unimodular gravity whose otherwise arbitrary cosmological constant is now determined as a Machian universal average. We prove that an empty space-time is necessarily Ricci tensor flat, and demonstrate the vanishing of the cosmological constant within the scalar field paradigm. The cosmological analysis, carried out at the mini-superspace level, reveals a vanishing cosmological constant for a universe which cannot be closed as long as gravity is attractive. Finally, we give an example of a normalized theory of gravity which does give rise to a non-zero cosmological constant.
Wang, Zhao-Qiang; Hu, Chang-Hua; Si, Xiao-Sheng; Zio, Enrico
2018-02-01
Current degradation modeling and remaining useful life prediction studies share a common assumption that the degrading systems are not maintained or maintained perfectly (i.e., to an as-good-as new state). This paper concerns the issues of how to model the degradation process and predict the remaining useful life of degrading systems subjected to imperfect maintenance activities, which can restore the health condition of a degrading system to any degradation level between as-good-as new and as-bad-as old. Toward this end, a nonlinear model driven by Wiener process is first proposed to characterize the degradation trajectory of the degrading system subjected to imperfect maintenance, where negative jumps are incorporated to quantify the influence of imperfect maintenance activities on the system's degradation. Then, the probability density function of the remaining useful life is derived analytically by a space-scale transformation, i.e., transforming the constructed degradation model with negative jumps crossing a constant threshold level to a Wiener process model crossing a random threshold level. To implement the proposed method, unknown parameters in the degradation model are estimated by the maximum likelihood estimation method. Finally, the proposed degradation modeling and remaining useful life prediction method are applied to a practical case of draught fans belonging to a kind of mechanical systems from steel mills. The results reveal that, for a degrading system subjected to imperfect maintenance, our proposed method can obtain more accurate remaining useful life predictions than those of the benchmark model in literature.
Fine-structure constant: Is it really a constant
International Nuclear Information System (INIS)
Bekenstein, J.D.
1982-01-01
It is often claimed that the fine-structure ''constant'' α is shown to be strictly constant in time by a variety of astronomical and geophysical results. These constrain its fractional rate of change alpha-dot/α to at least some orders of magnitude below the Hubble rate H 0 . We argue that the conclusion is not as straightforward as claimed since there are good physical reasons to expect alpha-dot/α 0 . We propose to decide the issue by constructing a framework for a variability based on very general assumptions: covariance, gauge invariance, causality, and time-reversal invariance of electromagnetism, as well as the idea that the Planck-Wheeler length (10 -33 cm) is the shortest scale allowable in any theory. The framework endows α with well-defined dynamics, and entails a modification of Maxwell electrodynamics. It proves very difficult to rule it out with purely electromagnetic experiments. In a cosmological setting, the framework predicts an alpha-dot/α which can be compatible with the astronomical constraints; hence, these are too insensitive to rule out α variability. There is marginal conflict with the geophysical constraints: however, no firm decision is possible because of uncertainty about various cosmological parameters. By contrast the framework's predictions for spatial gradients of α are in fatal conflict with the results of the Eoetvoes-Dicke-Braginsky experiments. Hence these tests of the equivalence principle rule out with confidence spacetime variability of α at any level
Potential constants and centrifugal distortion constants of octahedral hexafluoride molecules
Energy Technology Data Exchange (ETDEWEB)
Manivannan, G [Government Thirumagal Mill' s Coll., Gudiyattam, Tamil Nadu (India)
1981-04-01
The kinetic constants method outlined by Thirugnanasambandham (1964) based on Wilson's (1955) group theory has been adapted in evaluating the potential constants for SF/sub 6/, SeF/sub 6/, WF/sub 6/, IrF/sub 6/, UF/sub 6/, NpF/sub 6/, and PuF/sub 6/ using the experimentally observed vibrational frequency data. These constants are used to calculate the centrifugal distortion constants for the first time.
International Nuclear Information System (INIS)
Yu, Shanshan; Drouin, Brian J.; Miller, Charles E.
2014-01-01
We have updated the isotopically invariant Dunham fit of O 2 with newly reported literature transitions to derive (1) the energy levels, partition sums, band-by-band molecular constants, and RKR potentials for the X 3 Σ g − , a 1 Δ g , and b 1 Σ g + states of the six O 2 isotopologues: 16 O 16 O, 16 O 17 O, 16 O 18 O, 17 O 17 O, 17 O 18 O, and 18 O 18 O; (2) Franck-Condon factors for their a 1 Δ g −X 3 Σ g − , b 1 Σ g + −X 3 Σ g − , and a 1 Δ g −b 1 Σ g + band systems. This new spectroscopic parameterization characterizes all known transitions within and between the X 3 Σ g − , a 1 Δ g , and b 1 Σ g + states within experimental uncertainty and can be used for accurate predictions of as yet unmeasured transitions. All of these results are necessary to provide a consistent linelist of all transitions which will be reported in a followup paper
1995-08-01
about the distances to galaxies and thereby about the expansion rate of the Universe. A simple way to determine the distance to a remote galaxy is by measuring its redshift, calculate its velocity from the redshift and divide this by the Hubble constant, H0. For instance, the measured redshift of the parent galaxy of SN 1995K (0.478) yields a velocity of 116,000 km/sec, somewhat more than one-third of the speed of light (300,000 km/sec). From the universal expansion rate, described by the Hubble constant (H0 = 20 km/sec per million lightyears as found by some studies), this velocity would indicate a distance to the supernova and its parent galaxy of about 5,800 million lightyears. The explosion of the supernova would thus have taken place 5,800 million years ago, i.e. about 1,000 million years before the solar system was formed. However, such a simple calculation works only for relatively ``nearby'' objects, perhaps out to some hundred million lightyears. When we look much further into space, we also look far back in time and it is not excluded that the universal expansion rate, i.e. the Hubble constant, may have been different at earlier epochs. This means that unless we know the change of the Hubble constant with time, we cannot determine reliable distances of distant galaxies from their measured redshifts and velocities. At the same time, knowledge about such change or lack of the same will provide unique information about the time elapsed since the Universe began to expand (the ``Big Bang''), that is, the age of the Universe and also its ultimate fate. The Deceleration Parameter q0 Cosmologists are therefore eager to determine not only the current expansion rate (i.e., the Hubble constant, H0) but also its possible change with time (known as the deceleration parameter, q0). Although a highly accurate value of H0 has still not become available, increasing attention is now given to the observational determination of the second parameter, cf. also the Appendix at the
Association constants of telluronium salts
International Nuclear Information System (INIS)
Kovach, N.A.; Rivkin, B.B.; Sadekov, T.D.; Shvajka, O.P.
1996-01-01
Association constants in acetonitrile of triphenyl telluronium salts, which are dilute electrolytes, are determined through the conductometry method. Satisfactory correlation dependence of constants of interion association and threshold molar electroconductivity on the Litvinenko-Popov constants for depositing groups is identified. 6 refs
Anisotropic constant-roll inflation
Energy Technology Data Exchange (ETDEWEB)
Ito, Asuka; Soda, Jiro [Kobe University, Department of Physics, Kobe (Japan)
2018-01-15
We study constant-roll inflation in the presence of a gauge field coupled to an inflaton. By imposing the constant anisotropy condition, we find new exact anisotropic constant-roll inflationary solutions which include anisotropic power-law inflation as a special case. We also numerically show that the new anisotropic solutions are attractors in the phase space. (orig.)
Quintessence and the cosmological constant
International Nuclear Information System (INIS)
Doran, M.; Wetterich, C.
2003-01-01
Quintessence -- the energy density of a slowly evolving scalar field -- may constitute a dynamical form of the homogeneous dark energy in the universe. We review the basic idea in the light of the cosmological constant problem. Cosmological observations or a time variation of fundamental 'constants' can distinguish quintessence from a cosmological constant
Energy, stability and cosmological constant
International Nuclear Information System (INIS)
Deser, S.
1982-01-01
The definition of energy and its use in studying stability in general relativity are extended to the case when there is a nonvanishing cosmological constant Λ. Existence of energy is first demonstrated for any model (with arbitrary Λ). It is defined with respect to sets of solutions tending asymptotically to any background space possessing timelike Killing symmetry, and is both conserved and of flux integral form. When Λ O, small excitations about De Sitter space are stable inside the event horizon. Outside excitations can contribute negatively due to the Killing vector's flip at the horizon. This is a universal phenomenon associated with the possibility of Hawking radiation. Apart from this effect, the Λ>O theory appears to be stable, also at the semi-classical level. (author)
DEFF Research Database (Denmark)
Pawlowski, F; Jorgensen, P; Olsen, Jeppe
2002-01-01
A detailed study is carried out of the accuracy of molecular equilibrium geometries obtained from least-squares fits involving experimental rotational constants B(0) and sums of ab initio vibration-rotation interaction constants alpha(r)(B). The vibration-rotation interaction constants have been...... calculated for 18 single-configuration dominated molecules containing hydrogen and first-row atoms at various standard levels of ab initio theory. Comparisons with the experimental data and tests for the internal consistency of the calculations show that the equilibrium structures generated using Hartree......-Fock vibration-rotation interaction constants have an accuracy similar to that obtained by a direct minimization of the CCSD(T) energy. The most accurate vibration-rotation interaction constants are those calculated at the CCSD(T)/cc-pVQZ level. The equilibrium bond distances determined from these interaction...
Interacting universes and the cosmological constant
International Nuclear Information System (INIS)
Alonso-Serrano, A.; Bastos, C.; Bertolami, O.; Robles-Pérez, S.
2013-01-01
In this Letter it is studied the effects that an interaction scheme among universes can have in the values of their cosmological constants. In the case of two interacting universes, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. In the more general case of a chain of N interacting universes with periodic boundary conditions, the spectrum of the Hamiltonian splits into a large number of levels, each of them associated with a particular value of the cosmological constant, that can be occupied by single universes revealing a collective behavior that plainly shows that the multiverse is much more than the mere sum of its parts
Interacting universes and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Alonso-Serrano, A. [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Bastos, C. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Robles-Pérez, S., E-mail: salvarp@imaff.cfmac.csic.es [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Física Teórica, Universidad del País Vasco, Apartado 644, 48080 Bilbao (Spain)
2013-02-12
In this Letter it is studied the effects that an interaction scheme among universes can have in the values of their cosmological constants. In the case of two interacting universes, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. In the more general case of a chain of N interacting universes with periodic boundary conditions, the spectrum of the Hamiltonian splits into a large number of levels, each of them associated with a particular value of the cosmological constant, that can be occupied by single universes revealing a collective behavior that plainly shows that the multiverse is much more than the mere sum of its parts.
Elongational flow of polymer melts at constant strain rate, constant stress and constant force
Wagner, Manfred H.; Rolón-Garrido, Víctor H.
2013-04-01
Characterization of polymer melts in elongational flow is typically performed at constant elongational rate or rarely at constant tensile stress conditions. One of the disadvantages of these deformation modes is that they are hampered by the onset of "necking" instabilities according to the Considère criterion. Experiments at constant tensile force have been performed even more rarely, in spite of the fact that this deformation mode is free from necking instabilities and is of considerable industrial relevance as it is the correct analogue of steady fiber spinning. It is the objective of the present contribution to present for the first time a full experimental characterization of a long-chain branched polyethylene melt in elongational flow. Experiments were performed at constant elongation rate, constant tensile stress and constant tensile force by use of a Sentmanat Extensional Rheometer (SER) in combination with an Anton Paar MCR301 rotational rheometer. The accessible experimental window and experimental limitations are discussed. The experimental data are modelled by using the Wagner I model. Predictions of the steady-start elongational viscosity in constant strain rate and creep experiments are found to be identical, albeit only by extrapolation of the experimental data to Hencky strains of the order of 6. For constant stress experiments, a minimum in the strain rate and a corresponding maximum in the elongational viscosity is found at a Hencky strain of the order of 3, which, although larger than the steady-state value, follows roughly the general trend of the steady-state elongational viscosity. The constitutive analysis also reveals that constant tensile force experiments indicate a larger strain hardening potential than seen in constant elongation rate or constant tensile stress experiments. This may be indicative of the effect of necking under constant elongation rate or constant tensile stress conditions according to the Considère criterion.
Spectrophotometric determination of association constant
DEFF Research Database (Denmark)
2016-01-01
Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...
The Nature of the Cosmological Constant Problem
Maia, M. D.; Capistrano, A. J. S.; Monte, E. M.
General relativity postulates the Minkowski space-time as the standard (flat) geometry against which we compare all curved space-times and also as the gravitational ground state where particles, quantum fields and their vacua are defined. On the other hand, experimental evidences tell that there exists a non-zero cosmological constant, which implies in a deSitter ground state, which not compatible with the assumed Minkowski structure. Such inconsistency is an evidence of the missing standard of curvature in Riemann's geometry, which in general relativity manifests itself in the form of the cosmological constant problem. We show how the lack of a curvature standard in Riemann's geometry can be fixed by Nash's theorem on metric perturbations. The resulting higher dimensional gravitational theory is more general than general relativity, similar to brane-world gravity, but where the propagation of the gravitational field along the extra dimensions is a mathematical necessity, rather than a postulate. After a brief introduction to Nash's theorem, we show that the vacuum energy density must remain confined to four-dimensional space-times, but the cosmological constant resulting from the contracted Bianchi identity represents a gravitational term which is not confined. In this case, the comparison between the vacuum energy and the cosmological constant in general relativity does not make sense. Instead, the geometrical fix provided by Nash's theorem suggests that the vacuum energy density contributes to the perturbations of the gravitational field.
Fish remains and humankind: part two
Directory of Open Access Journals (Sweden)
Andrew K G Jones
1998-07-01
Full Text Available The significance of aquatic resources to past human groups is not adequately reflected in the published literature - a deficiency which is gradually being acknowledged by the archaeological community world-wide. The publication of the following three papers goes some way to redress this problem. Originally presented at an International Council of Archaeozoology (ICAZ Fish Remains Working Group meeting in York, U.K. in 1987, these papers offer clear evidence of the range of interest in ancient fish remains across the world. Further papers from the York meeting were published in Internet Archaeology 3 in 1997.
Why Agricultural Educators Remain in the Classroom
Crutchfield, Nina; Ritz, Rudy; Burris, Scott
2013-01-01
The purpose of this study was to identify and describe factors that are related to agricultural educator career retention and to explore the relationships between work engagement, work-life balance, occupational commitment, and personal and career factors as related to the decision to remain in the teaching profession. The target population for…
Juveniles' Motivations for Remaining in Prostitution
Hwang, Shu-Ling; Bedford, Olwen
2004-01-01
Qualitative data from in-depth interviews were collected in 1990-1991, 1992, and 2000 with 49 prostituted juveniles remanded to two rehabilitation centers in Taiwan. These data are analyzed to explore Taiwanese prostituted juveniles' feelings about themselves and their work, their motivations for remaining in prostitution, and their difficulties…
Kadav Moun PSA (:60) (Human Remains)
Centers for Disease Control (CDC) Podcasts
2010-02-18
This is an important public health announcement about safety precautions for those handling human remains. Language: Haitian Creole. Created: 2/18/2010 by Centers for Disease Control and Prevention (CDC). Date Released: 2/18/2010.
The Annuity Puzzle Remains a Puzzle
Peijnenburg, J.M.J.; Werker, Bas; Nijman, Theo
We examine incomplete annuity menus and background risk as possible drivers of divergence from full annuitization. Contrary to what is often suggested in the literature, we find that full annuitization remains optimal if saving is possible after retirement. This holds irrespective of whether real or
Varying Constants, Gravitation and Cosmology
Directory of Open Access Journals (Sweden)
Jean-Philippe Uzan
2011-03-01
Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.
Directory of Open Access Journals (Sweden)
Joanna Durrant
2015-07-01
Full Text Available Exposure to constant light has a range of negative effects on behaviour and physiology, including reduced immune function in both vertebrates and invertebrates. It is proposed that the associated suppression of melatonin (a ubiquitous hormone and powerful antioxidant in response to the presence of light at night could be an underlying mechanistic link driving the changes to immune function. Here, we investigated the relationship between constant illumination, melatonin and immune function, using a model invertebrate species, the Australian black field cricket, Teleogryllus commodus. Crickets were reared under either a 12 h light: 12 h dark regimen or a constant 24 h light regimen. Circulating melatonin concentration and immune function (haemocyte concentration, lytic activity and phenoloxidase (PO activity were assessed in individual adult crickets through the analysis of haemolymph. Constant illumination reduced melatonin and had a negative impact on haemocyte concentrations and lytic activity, but its effect on PO activity was less apparent. Our data provide the first evidence, to our knowledge, of a link between exposure to constant illumination and variation in haemocyte concentration in an invertebrate model, while also highlighting the potential complexity of the immune response following exposure to constant illumination. This study provides insight into the possible negative effect of artificial night-time lighting on the physiology of invertebrates, but whether lower and potentially more ecologically relevant levels of light at night produce comparable results, as has been reported in several vertebrate taxa, remains to be tested.
Stabilized power constant alimentation; Alimentation regulee a puissance constante
Energy Technology Data Exchange (ETDEWEB)
Roussel, L [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1968-06-01
The study and realization of a stabilized power alimentation variable from 5 to 100 watts are described. In order to realize a constant power drift of Lithium compensated diodes, we have searched a 1 per cent precision of regulation and a response time minus than 1 sec. Recent components like Hall multiplicator and integrated amplifiers give this possibility and it is easy to use permutable circuits. (author) [French] On decrit l'etude et la realisation d'une alimentation a puissance constante reglable dans une gamme de 5 a 100 watts. Prevue pour le drift a puissance constante des diodes compensees au lithium, l'etude a ete menee en vue d'obtenir une precision de regulation de 1 pour cent et un temps de reponse inferieur a la seconde. Des systemes recents tels que multiplicateurs a effet Hall et circuits integres ont permis d'atteindre ce but tout en facilitant l'emploi de modules interchangeables. (auteur)
From the Rydberg constant to the fundamental constants metrology
International Nuclear Information System (INIS)
Nez, F.
2005-06-01
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Explosives remain preferred methods for platform abandonment
International Nuclear Information System (INIS)
Pulsipher, A.; Daniel, W. IV; Kiesler, J.E.; Mackey, V. III
1996-01-01
Economics and safety concerns indicate that methods involving explosives remain the most practical and cost-effective means for abandoning oil and gas structures in the Gulf of Mexico. A decade has passed since 51 dead sea turtles, many endangered Kemp's Ridleys, washed ashore on the Texas coast shortly after explosives helped remove several offshore platforms. Although no relationship between the explosions and the dead turtles was ever established, in response to widespread public concern, the US Minerals Management Service (MMS) and National Marine Fisheries Service (NMFS) implemented regulations limiting the size and timing of explosive charges. Also, more importantly, they required that operators pay for observers to survey waters surrounding platforms scheduled for removal for 48 hr before any detonations. If observers spot sea turtles or marine mammals within the danger zone, the platform abandonment is delayed until the turtles leave or are removed. However, concern about the effects of explosives on marine life remains
Learning Read-constant Polynomials of Constant Degree modulo Composites
DEFF Research Database (Denmark)
Chattopadhyay, Arkadev; Gavaldá, Richard; Hansen, Kristoffer Arnsfelt
2011-01-01
Boolean functions that have constant degree polynomial representation over a fixed finite ring form a natural and strict subclass of the complexity class \\textACC0ACC0. They are also precisely the functions computable efficiently by programs over fixed and finite nilpotent groups. This class...... is not known to be learnable in any reasonable learning model. In this paper, we provide a deterministic polynomial time algorithm for learning Boolean functions represented by polynomials of constant degree over arbitrary finite rings from membership queries, with the additional constraint that each variable...
TASI Lectures on the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Bousso, Raphael; Bousso, Raphael
2007-08-30
The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant over large spacetime regions. This can explain the observed value, but only in a theory satisfying a number of restrictive kinematic and dynamical conditions. String theory offers a concrete realization through its landscape of metastable vacua.
Xue, Y.; van der Laak, J.; Smedts, F.; Schoots, C.; Verhofstad, A.; de la Rosette, J.; Schalken, J.
2000-01-01
Knowledge concerning differentiation of neuroendocrine (NE) cells during development of the human prostate is rather fragmentary. Using immunohistochemistry combined with a morphometric method, we investigated the distribution and density of NE cells in the developing human prostate, with special
Energy Technology Data Exchange (ETDEWEB)
Nez, F
2005-06-15
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Systematics of constant roll inflation
Anguelova, Lilia; Suranyi, Peter; Wijewardhana, L. C. R.
2018-02-01
We study constant roll inflation systematically. This is a regime, in which the slow roll approximation can be violated. It has long been thought that this approximation is necessary for agreement with observations. However, recently it was understood that there can be inflationary models with a constant, and not necessarily small, rate of roll that are both stable and compatible with the observational constraint ns ≈ 1. We investigate systematically the condition for such a constant-roll regime. In the process, we find a whole new class of inflationary models, in addition to the known solutions. We show that the new models are stable under scalar perturbations. Finally, we find a part of their parameter space, in which they produce a nearly scale-invariant scalar power spectrum, as needed for observational viability.
Strain fluctuations and elastic constants
Energy Technology Data Exchange (ETDEWEB)
Parrinello, M.; Rahman, A.
1982-03-01
It is shown that the elastic strain fluctuations are a direct measure of elastic compliances in a general anisotropic medium; depending on the ensemble in which the fluctuation is measured either the isothermal or the adiabatic compliances are obtained. These fluctuations can now be calculated in a constant enthalpy and pressure, and hence, constant entropy, ensemble due to recent develpments in the molecular dynamics techniques. A calculation for a Ni single crystal under uniform uniaxial 100 tensile or compressive load is presented as an illustration of the relationships derived between various strain fluctuations and the elastic modulii. The Born stability criteria and the behavior of strain fluctuations are shown to be related.
Decomposition Technique for Remaining Useful Life Prediction
Saha, Bhaskar (Inventor); Goebel, Kai F. (Inventor); Saxena, Abhinav (Inventor); Celaya, Jose R. (Inventor)
2014-01-01
The prognostic tool disclosed here decomposes the problem of estimating the remaining useful life (RUL) of a component or sub-system into two separate regression problems: the feature-to-damage mapping and the operational conditions-to-damage-rate mapping. These maps are initially generated in off-line mode. One or more regression algorithms are used to generate each of these maps from measurements (and features derived from these), operational conditions, and ground truth information. This decomposition technique allows for the explicit quantification and management of different sources of uncertainty present in the process. Next, the maps are used in an on-line mode where run-time data (sensor measurements and operational conditions) are used in conjunction with the maps generated in off-line mode to estimate both current damage state as well as future damage accumulation. Remaining life is computed by subtracting the instance when the extrapolated damage reaches the failure threshold from the instance when the prediction is made.
Industry remains stuck in a transitional mode
International Nuclear Information System (INIS)
Garb, F.A.
1991-01-01
The near future for industry remains foggy for several obvious reasons. The shake-up of the Soviet Union and how the pieces will reform remains unclear. How successful efforts are to privatize government oil company operations around the world has yet to be determined. A long sought peace in the Middle East seems to be inching closer, but will this continue? If it does continue, what impact will it have on world energy policy? Will American companies, which are now transferring their attention to foreign E and P, also maintain an interest in domestic activities? Is the U.S. economy really on the upswing? We are told that the worst of the recession is over, but try telling this to thousands of workers in the oil patch who are being released monthly by the big players in domestic operations. This paper reports that 1992 should be a better year than 1991, if measured in opportunity. There are more exploration and acquisition options available, both domestically and internationally, than there have been in years. Probably more opportunities exist than there are players-certainly more than can be funded with current financial resources
Universal relation between spectroscopic constants
Indian Academy of Sciences (India)
(3) The author has used eq. (6) of his paper to calculate De. This relation leads to a large deviation from the correct value depending upon the extent to which experimental values are known. Guided by this fact, in our work, we used experimentally observed De values to derive the relation between spectroscopic constants.
Tachyon constant-roll inflation
Mohammadi, A.; Saaidi, Kh.; Golanbari, T.
2018-04-01
The constant-roll inflation is studied where the inflaton is taken as a tachyon field. Based on this approach, the second slow-roll parameter is taken as a constant which leads to a differential equation for the Hubble parameter. Finding an exact solution for the Hubble parameter is difficult and leads us to a numerical solution for the Hubble parameter. On the other hand, since in this formalism the slow-roll parameter η is constant and could not be assumed to be necessarily small, the perturbation parameters should be reconsidered again which, in turn, results in new terms appearing in the amplitude of scalar perturbations and the scalar spectral index. Utilizing the numerical solution for the Hubble parameter, we estimate the perturbation parameter at the horizon exit time and compare it with observational data. The results show that, for specific values of the constant parameter η , we could have an almost scale-invariant amplitude of scalar perturbations. Finally, the attractor behavior for the solution of the model is presented, and we determine that the feature could be properly satisfied.
Shotgun microbial profiling of fossil remains
DEFF Research Database (Denmark)
Der Sarkissian, Clio; Ermini, Luca; Jónsson, Hákon
2014-01-01
the specimen of interest, but instead reflect environmental organisms that colonized the specimen after death. Here, we characterize the microbial diversity recovered from seven c. 200- to 13 000-year-old horse bones collected from northern Siberia. We use a robust, taxonomy-based assignment approach...... to identify the microorganisms present in ancient DNA extracts and quantify their relative abundance. Our results suggest that molecular preservation niches exist within ancient samples that can potentially be used to characterize the environments from which the remains are recovered. In addition, microbial...... community profiling of the seven specimens revealed site-specific environmental signatures. These microbial communities appear to comprise mainly organisms that colonized the fossils recently. Our approach significantly extends the amount of useful data that can be recovered from ancient specimens using...
Some remaining problems in HCDA analysis
International Nuclear Information System (INIS)
Chang, Y.W.
1981-01-01
The safety assessment and licensing of liquid-metal fast breeder reactors (LMFBRs) requires an analysis on the capability of the reactor primary system to sustain the consequences of a hypothetical core-disruptive accident (HCDA). Although computational methods and computer programs developed for HCDA analyses can predict reasonably well the response of the primary containment system, and follow up the phenomena of HCDA from the start of excursion to the time of dynamic equilibrium in the system, there remain areas in the HCDA analysis that merit further analytical and experimental studies. These are the analysis of fluid impact on reactor cover, three-dimensional analysis, the treatment of the perforated plates, material properties under high strain rates and under high temperatures, the treatment of multifield flows, and the treatment of prestressed concrete reactor vessels. The purpose of this paper is to discuss the structural mechanics of HCDA analysis in these areas where improvements are needed
Political, energy events will remain interwoven
International Nuclear Information System (INIS)
Jones, D.P.
1991-01-01
This paper reports that it is possible to discuss the significance of political and energy events separately, but, in truth, they are intricately interwoven. Furthermore, there are those who will argue that since the two are inseparable, the future is not predictable; so why bother in the endeavor. It is possible that the central point of the exercise may have been missed-yes, the future is unpredictable exclamation point However, the objective of prediction is secondary. The objective of understanding the dynamic forces of change is primary exclamation point With this view of recent history, it is perhaps appropriate to pause and think about the future of the petroleum industry. The future as shaped by political, energy, economic, environmental and technological forces will direct our lives and markets during this decade. Most importantly, what will be the direction that successful businesses take to remain competitive in a global environment? These are interesting issues worthy of provocative thoughts and innovative ideas
Nuclear remains an economic and ecologic asset
International Nuclear Information System (INIS)
Le Ngoc, Boris
2015-01-01
The author herein outlines the several benefits of nuclear energy and nuclear industry for France. He first outlines that France possesses 97 per cent of de-carbonated electricity thanks to nuclear energy (77 pc) and renewable energies (20 pc, mainly hydraulic), and that renewable energies must be developed in the building and transport sectors to be able to get rid of the environmentally and financially costly fossil energies. He outlines that reactor maintenance and the nuclear fuel cycle industry are fields of technological leadership for the French nuclear industry which is, after motor industry and aircraft industry, the third industrial sector in France. He indicates that nuclear electricity is to remain the most competitive one, and that nuclear energy and renewable energies must not be opposed to it but considered as complementary in the struggle against climate change, i.e. to reduce greenhouse gas emissions and to get rid of the prevalence of fossil energies
Population cycles: generalities, exceptions and remaining mysteries
2018-01-01
Population cycles are one of nature's great mysteries. For almost a hundred years, innumerable studies have probed the causes of cyclic dynamics in snowshoe hares, voles and lemmings, forest Lepidoptera and grouse. Even though cyclic species have very different life histories, similarities in mechanisms related to their dynamics are apparent. In addition to high reproductive rates and density-related mortality from predators, pathogens or parasitoids, other characteristics include transgenerational reduced reproduction and dispersal with increasing-peak densities, and genetic similarity among populations. Experiments to stop cyclic dynamics and comparisons of cyclic and noncyclic populations provide some understanding but both reproduction and mortality must be considered. What determines variation in amplitude and periodicity of population outbreaks remains a mystery. PMID:29563267
Does hypertension remain after kidney transplantation?
Directory of Open Access Journals (Sweden)
Gholamreza Pourmand
2015-05-01
Full Text Available Hypertension is a common complication of kidney transplantation with the prevalence of 80%. Studies in adults have shown a high prevalence of hypertension (HTN in the first three months of transplantation while this rate is reduced to 50- 60% at the end of the first year. HTN remains as a major risk factor for cardiovascular diseases, lower graft survival rates and poor function of transplanted kidney in adults and children. In this retrospective study, medical records of 400 kidney transplantation patients of Sina Hospital were evaluated. Patients were followed monthly for the 1st year, every two months in the 2nd year and every three months after that. In this study 244 (61% patients were male. Mean ± SD age of recipients was 39.3 ± 13.8 years. In most patients (40.8% the cause of end-stage renal disease (ESRD was unknown followed by HTN (26.3%. A total of 166 (41.5% patients had been hypertensive before transplantation and 234 (58.5% had normal blood pressure. Among these 234 individuals, 94 (40.2% developed post-transplantation HTN. On the other hand, among 166 pre-transplant hypertensive patients, 86 patients (56.8% remained hypertensive after transplantation. Totally 180 (45% patients had post-transplantation HTN and 220 patients (55% didn't develop HTN. Based on the findings, the incidence of post-transplantation hypertension is high, and kidney transplantation does not lead to remission of hypertension. On the other hand, hypertension is one of the main causes of ESRD. Thus, early screening of hypertension can prevent kidney damage and reduce further problems in renal transplant recipients.
Stabilized power constant alimentation; Alimentation regulee a puissance constante
Energy Technology Data Exchange (ETDEWEB)
Roussel, L. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1968-06-01
The study and realization of a stabilized power alimentation variable from 5 to 100 watts are described. In order to realize a constant power drift of Lithium compensated diodes, we have searched a 1 per cent precision of regulation and a response time minus than 1 sec. Recent components like Hall multiplicator and integrated amplifiers give this possibility and it is easy to use permutable circuits. (author) [French] On decrit l'etude et la realisation d'une alimentation a puissance constante reglable dans une gamme de 5 a 100 watts. Prevue pour le drift a puissance constante des diodes compensees au lithium, l'etude a ete menee en vue d'obtenir une precision de regulation de 1 pour cent et un temps de reponse inferieur a la seconde. Des systemes recents tels que multiplicateurs a effet Hall et circuits integres ont permis d'atteindre ce but tout en facilitant l'emploi de modules interchangeables. (auteur)
The Human Remains from HMS Pandora
Directory of Open Access Journals (Sweden)
D.P. Steptoe
2002-04-01
Full Text Available In 1977 the wreck of HMS Pandora (the ship that was sent to re-capture the Bounty mutineers was discovered off the north coast of Queensland. Since 1983, the Queensland Museum Maritime Archaeology section has carried out systematic excavation of the wreck. During the years 1986 and 1995-1998, more than 200 human bone and bone fragments were recovered. Osteological investigation revealed that this material represented three males. Their ages were estimated at approximately 17 +/-2 years, 22 +/-3 years and 28 +/-4 years, with statures of 168 +/-4cm, 167 +/-4cm, and 166cm +/-3cm respectively. All three individuals were probably Caucasian, although precise determination of ethnicity was not possible. In addition to poor dental hygiene, signs of chronic diseases suggestive of rickets and syphilis were observed. Evidence of spina bifida was seen on one of the skeletons, as were other skeletal anomalies. Various taphonomic processes affecting the remains were also observed and described. Compact bone was observed under the scanning electron microscope and found to be structurally coherent. Profiles of the three skeletons were compared with historical information about the 35 men lost with the ship, but no precise identification could be made. The investigation did not reveal the cause of death. Further research, such as DNA analysis, is being carried out at the time of publication.
SMART POINT CLOUD: DEFINITION AND REMAINING CHALLENGES
Directory of Open Access Journals (Sweden)
F. Poux
2016-10-01
Full Text Available Dealing with coloured point cloud acquired from terrestrial laser scanner, this paper identifies remaining challenges for a new data structure: the smart point cloud. This concept arises with the statement that massive and discretized spatial information from active remote sensing technology is often underused due to data mining limitations. The generalisation of point cloud data associated with the heterogeneity and temporality of such datasets is the main issue regarding structure, segmentation, classification, and interaction for an immediate understanding. We propose to use both point cloud properties and human knowledge through machine learning to rapidly extract pertinent information, using user-centered information (smart data rather than raw data. A review of feature detection, machine learning frameworks and database systems indexed both for mining queries and data visualisation is studied. Based on existing approaches, we propose a new 3-block flexible framework around device expertise, analytic expertise and domain base reflexion. This contribution serves as the first step for the realisation of a comprehensive smart point cloud data structure.
Cosmological constant in the quantum multiverse
International Nuclear Information System (INIS)
Larsen, Grant; Nomura, Yasunori; Roberts, Hannes L. L.
2011-01-01
Recently, a new framework for describing the multiverse has been proposed which is based on the principles of quantum mechanics. The framework allows for well-defined predictions, both regarding global properties of the universe and outcomes of particular experiments, according to a single probability formula. This provides complete unification of the eternally inflating multiverse and many worlds in quantum mechanics. In this paper, we elucidate how cosmological parameters can be calculated in this framework, and study the probability distribution for the value of the cosmological constant. We consider both positive and negative values, and find that the observed value is consistent with the calculated distribution at an order of magnitude level. In particular, in contrast to the case of earlier measure proposals, our framework prefers a positive cosmological constant over a negative one. These results depend only moderately on how we model galaxy formation and life evolution therein.
Calculation of magnetic hyperfine constants
International Nuclear Information System (INIS)
Bufaical, R.F.; Maffeo, B.; Brandi, H.S.
1975-01-01
The magnetic hyperfine constants of the V sub(K) center in CaF 2 , SrF 2 and BaF 2 have been calculated assuming a phenomenological model, based on the F 2 - 'central molucule', to describe the wavefunction of the defect. Calculations have shown that introduction of a small degree of covalence, between this central molecule and neighboring ions, is necessary to improve the electronic structure description of the defect. It was also shown that the results for the hyperfine constants are strongly dependent on the relaxations of the ions neighboring the central molecule; these relaxations have been determined by fitting the experimental data. The present results are compared with other previous calculations where similar and different theoretical methods have been used
On the gravitational constant change
International Nuclear Information System (INIS)
Milyukov, V.K.
1986-01-01
The nowadays viewpoint on the problem of G gravitational constant invariability is presented in brief. The methods and results of checking of the G dependence on the nature of substance (checking of the equivalence principle), G dependepce on distance (checking of Newton gravity law) and time (cosmological experiments) are presented. It is pointed out that all performed experiments don't give any reasons to have doubts in G constancy in space and time and G independence on the nature of the substance
Photodissociation constant of NO2
International Nuclear Information System (INIS)
Nootebos, M.A.; Bange, P.
1992-01-01
The velocity of the dissociation of NO 2 into ozone and NO mainly depends on the ultraviolet sunlight quantity, and with that the cloudiness. A correct value for this reaction constant is important for the accurate modelling of O 3 - and NO 2 -concentrations in plumes of electric power plants, in particular in the case of determination of the amount of photochemical summer smog. An advanced signal processing method (deconvolution, correlation) was applied on the measurements. The measurements were carried out from aeroplanes
What remains of the Arrow oil?
International Nuclear Information System (INIS)
Sergy, G.; Owens, E.
1993-01-01
In February 1970, the tanker Arrow became grounded 6.5 km off the north shore of Chedabucto Bay, Nova Scotia, and nearly 72,000 bbl of Bunker C fuel oil were released from the vessel during its subsequent breakup and sinking. The oil was washed ashore in various degrees over an estimated 305 km of the bay's 604-km shoreline, of which only 48 km were cleaned. In addition, the tanker Kurdistan broke in two in pack ice in March 1979 in the Cabot Strait area, spilling ca 54,000 bbl of Bunker C, some of which was later found at 16 locations along the northeast and east shorelines of Chedabucto Bay. In summer 1992, a systematic ground survey of the bay's shorelines was conducted using Environment Canada Shoreline Cleanup Assessment Team (SCAT) procedures. Standard observations were made of oil distribution and width, thickness, and character of the oil residues in 419 coastal segments. Results from the survey are summarized. Oil was found to be present on 13.3 km of the shoreline, with heavy oiling restricted to 1.3 km primarily in the areas of Black Duck Cove and Lennox Passage. Some of this residual oil was identified as coming from the Arrow. Natural weathering processes account for removal of most of the spilled oil from the bay. Oil remaining on the shore was found in areas outside of the zone of physical wave action, in areas of nearshore mixing where fine sediments are not present to weather the oil through biophysical processes, or in crusts formed by oil weathered on the surface. The systematic description of oiled shorelines using the SCAT methodology proved very successful, even for such an old spill. 6 refs
Ghost Remains After Black Hole Eruption
2009-05-01
NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after
Fate of nuclear waste site remains unclear
International Nuclear Information System (INIS)
Anderson, E.V.
1980-01-01
The only commercial nuclear fuel reprocessing plant in the U.S., located in West Valley, N.Y., has been shut down since 1972, and no efforts have yet been made to clean up the site. The site contains a spent-fuel pool, high level liquid waste storage tanks, and two radioactive waste burial grounds. Nuclear Fuel Services, Inc., has been leasing the site from the New York State Energy RandD Authority. Federal litigation may ensue, prompted by NRC and DOE, if the company refuses to decontaminate the area when its lease expires at the end of 1980. DOE has developed a plan to solidify the liquid wastes at the facility but needs additional legislation and funding to implement the scheme
Oil prices remain firm, despite economic slump
International Nuclear Information System (INIS)
Brady, Aaron; Giesecke Linda
2002-01-01
Despite all the evidence of sluggish economic growth throughout the world this year, WTI crude oil prices have averaged about $24/bbl year-to-date. Although prices have been lower than year-ago levels, they're a far cry from the lows that occurred in 1998 and at the beginning of 1999. Mounting tensions in the Middle East have given crude prices support. While the market has taken these tensions into account since the beginning of the year, more recent concerns about a possible U.S military conflict with Iraq have added a larger war premium to crude prices. Note that the halt of Iraqi exports itself may not be as detrimental as perceived, since these exports could easily be replaced by OPEC's excess capacity. In part, we have already seen a reduction in Iraqi exports this year due to a pricing dispute
International Nuclear Information System (INIS)
Mangus, J.D.; Redding, A.H.
1975-01-01
A system for maintaining two distinct sodium levels within the shell of a heat exchanger having a plurality of J-shaped modular tube bundles each enclosed in a separate shell which extends from a common base portion. A lower liquid level is maintained in the base portion and an upper liquid level is maintained in the shell enwrapping the long stem of the J-shaped tube bundles by utilizing standpipes with a notch at the lower end which decreases in open area the distance from the end of the stand pipe increases and a supply of inert gas fed at a constant rate to produce liquid levels, which will remain generally constant as the flow of liquid through the vessel varies
International Nuclear Information System (INIS)
Boikova, N.A.; Kleshchevskaya, S.V.; Tyukhtyaev, Yu.N.; Faustov, R.N.
2004-01-01
A high-precision investigation of a logarithmic contribution in the particle-mass ratio to the fine shift of the S energy levels of hydrogen-like atoms from the exchange of a Coulomb photon is performed. It is shown that diagrams describing the exchange of one transverse photon and two Coulomb photons do not make such contributions
Chandra Independently Determines Hubble Constant
2006-08-01
A critically important number that specifies the expansion rate of the Universe, the so-called Hubble constant, has been independently determined using NASA's Chandra X-ray Observatory. This new value matches recent measurements using other methods and extends their validity to greater distances, thus allowing astronomers to probe earlier epochs in the evolution of the Universe. "The reason this result is so significant is that we need the Hubble constant to tell us the size of the Universe, its age, and how much matter it contains," said Max Bonamente from the University of Alabama in Huntsville and NASA's Marshall Space Flight Center (MSFC) in Huntsville, Ala., lead author on the paper describing the results. "Astronomers absolutely need to trust this number because we use it for countless calculations." Illustration of Sunyaev-Zeldovich Effect Illustration of Sunyaev-Zeldovich Effect The Hubble constant is calculated by measuring the speed at which objects are moving away from us and dividing by their distance. Most of the previous attempts to determine the Hubble constant have involved using a multi-step, or distance ladder, approach in which the distance to nearby galaxies is used as the basis for determining greater distances. The most common approach has been to use a well-studied type of pulsating star known as a Cepheid variable, in conjunction with more distant supernovae to trace distances across the Universe. Scientists using this method and observations from the Hubble Space Telescope were able to measure the Hubble constant to within 10%. However, only independent checks would give them the confidence they desired, considering that much of our understanding of the Universe hangs in the balance. Chandra X-ray Image of MACS J1149.5+223 Chandra X-ray Image of MACS J1149.5+223 By combining X-ray data from Chandra with radio observations of galaxy clusters, the team determined the distances to 38 galaxy clusters ranging from 1.4 billion to 9.3 billion
Low power constant fraction discriminator
International Nuclear Information System (INIS)
Krishnan, Shanti; Raut, S.M.; Mukhopadhyay, P.K.
2001-01-01
This paper describes the design of a low power ultrafast constant fraction discriminator, which significantly reduces the power consumption. A conventional fast discriminator consumes about 1250 MW of power whereas this low power version consumes about 440 MW. In a multi detector system, where the number of discriminators is very large, reduction of power is of utmost importance. This low power discriminator is being designed for GRACE (Gamma Ray Atmospheric Cerenkov Experiments) telescope where 1000 channels of discriminators are required. A novel method of decreasing power consumption has been described. (author)
Can coupling constants be related
International Nuclear Information System (INIS)
Nandi, Satyanarayan; Ng, Wing-Chiu.
1978-06-01
We analyze the conditions under which several coupling constants in field theory can be related to each other. When the relation is independent of the renormalization point, the relation between any g and g' must satisfy a differential equation as follows from the renormalization group equations. Using this differential equation, we investigate the criteria for the feasibility of a power-series relation for various theories, especially the Weinberg-Salam type (including Higgs bosons) with an arbitrary number of quark and lepton flavors. (orig./WL) [de
Exact constants in approximation theory
Korneichuk, N
1991-01-01
This book is intended as a self-contained introduction for non-specialists, or as a reference work for experts, to the particular area of approximation theory that is concerned with exact constants. The results apply mainly to extremal problems in approximation theory, which in turn are closely related to numerical analysis and optimization. The book encompasses a wide range of questions and problems: best approximation by polynomials and splines; linear approximation methods, such as spline-approximation; optimal reconstruction of functions and linear functionals. Many of the results are base
Hydrodynamic constants from cosmic censorship
International Nuclear Information System (INIS)
Nakamura, Shin
2008-01-01
We study a gravity dual of Bjorken flow of N=4 SYM-theory plasma. We point out that the cosmic censorship hypothesis may explain why the regularity of the dual geometry constrains the hydrodynamic constants. We also investigate the apparent horizon of the dual geometry. We find that the dual geometry constructed on Fefferman-Graham (FG) coordinates is not appropriate for examination of the apparent horizon since the coordinates do not cover the trapped region. However, the preliminary analysis on FG coordinates suggests that the location of the apparent horizon is very sensitive to the hydrodynamic parameters. (author)
Remaining Calm in the Midst of Chaos
International Nuclear Information System (INIS)
Sullivan, Robin S.; Ryan, Grant W.; Young, Jonathan
2004-01-01
level of order in this seemingly chaotic situation. While the specifics of the safety basis strategy for the K Basins sludge removal project will be described in the paper, the general concepts of the strategy are applicable to similar projects throughout the DOE complex
Asymptotics with a positive cosmological constant II
Kesavan, Aruna; Ashtekar, Abhay; Bonga, Beatrice
2015-04-01
The study of isolated systems has been vastly successful in the context of vanishing cosmological constant, Λ = 0 . However, there is no physically useful notion of asymptotics for the universe we inhabit with Λ > 0 . This means that presently there is no fundamental understanding of gravitational waves in our own universe. The full non-linear framework is still under development, but some interesting results at the linearized level have been obtained. In particular, I will discuss the quadrupole formula for gravitational radiation and its implications.
Relaxing a large cosmological constant
International Nuclear Information System (INIS)
Bauer, Florian; Sola, Joan; Stefancic, Hrvoje
2009-01-01
The cosmological constant (CC) problem is the biggest enigma of theoretical physics ever. In recent times, it has been rephrased as the dark energy (DE) problem in order to encompass a wider spectrum of possibilities. It is, in any case, a polyhedric puzzle with many faces, including the cosmic coincidence problem, i.e. why the density of matter ρ m is presently so close to the CC density ρ Λ . However, the oldest, toughest and most intriguing face of this polyhedron is the big CC problem, namely why the measured value of ρ Λ at present is so small as compared to any typical density scale existing in high energy physics, especially taking into account the many phase transitions that our Universe has undergone since the early times, including inflation. In this Letter, we propose to extend the field equations of General Relativity by including a class of invariant terms that automatically relax the value of the CC irrespective of the initial size of the vacuum energy in the early epochs. We show that, at late times, the Universe enters an eternal de Sitter stage mimicking a tiny positive cosmological constant. Thus, these models could be able to solve the big CC problem without fine-tuning and have also a bearing on the cosmic coincidence problem. Remarkably, they mimic the ΛCDM model to a large extent, but they still leave some characteristic imprints that should be testable in the next generation of experiments.
Higgs inflation and the cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2014-02-15
The Higgs not only induces the masses of all SM particles, the Higgs, given its special mass value, is the natural candidate for the inflaton and in fact is ruling the evolution of the early universe, by providing the necessary dark energy which remains the dominant energy density. SM running couplings not only allow us to extrapolate SM physics up to the Planck scale, but equally important they are triggering the Higgs mechanism. This is possible by the fact that the bare mass term in the Higgs potential changes sign at about μ{sub 0}≅1.40 x 10{sup 16} GeV and in the symmetric phase is enhanced by quadratic terms in the Planck mass. Such a huge Higgs mass term is able to play a key role in triggering inflation in the early universe. In this article we extend our previous investigation by working out the details of a Higgs inflation scenario. We show how different terms contributing to the Higgs Lagrangian are affecting inflation. Given the SM and its extrapolation to scales μ>μ{sub 0} we find a calculable cosmological constant V(0) which is weakly scale dependent and actually remains large during inflation. This is different to the Higgs fluctuation field dependent ΔV(φ), which decays exponentially during inflation, and actually would not provide a sufficient amount of inflation. The fluctuation field has a different effective mass which shifts the bare Higgs transition point to a lower value μ'{sub 0} ≅7.7 x 10{sup 14} GeV. The vacuum energy V(0) being proportional to M{sub Pl}{sup 4} has a coefficient which vanishes near the Higgs transition point, such that the bare and the renormalized cosmological constant match at this point. The role of the Higgs in reheating and baryogenesis is emphasized.
Formas estructurales de fuerza constante
Directory of Open Access Journals (Sweden)
Zalewski, Waclaw
1963-05-01
Full Text Available The author seeks to prove the need to obtain the most essential form in the various types of structures by applying a number of rational principles, of which the constant stress principle is one of the most decisive. The structural form should be a logical consequence of all its functional circumstances, and this requires a clear understanding of the general behaviour of each part of the structure, and also of the main stresses which operate on it, considered as a unitary whole. To complete his theoretical argument, the author gives some examples, in the design of which the criterion of constant stress has been adopted. The author considers the various aspects which are involved in obtaining a structural design that satisfies given functional and aesthetic requirements. In doing so he refers to his personal experience within Poland, and infers technical principles of general validity which should determine the rational design of the form, as an integrated aspect of the structural pattern. The projects which illustrate this paper are Polish designs of undoubted constructive significance, in which the principle of constant stress has been applied. Finally the author condenses his whole theory in a simple and straightforward practical formula, which should be followed if a truly rational form is to be achieved: the constancy of stress in the various structural elements.El autor se esfuerza en mostrar la necesidad de llegar a la forma real en las distintas estructuras siguiendo una serie de principios racionales, entre los que domina el criterio de la fuerza constante. La forma ha de ser una consecuencia lógica en todos sus aspectos, y esto exige un claro conocimiento del comportamiento general de cada una de las partes de la estructura, y de los esfuerzos generales que dominan en la misma al considerarla como un todo. Para completar la exposición de orden teórico, el autor presenta algunos ejemplos en cuyo proyecto se ha seguido el criterio de
Constant Proportion Debt Obligations (CPDOs)
DEFF Research Database (Denmark)
Cont, Rama; Jessen, Cathrine
2012-01-01
be made arbitrarily small—and thus the credit rating arbitrarily high—by increasing leverage, but the ratings obtained strongly depend on assumptions on the credit environment (high spread or low spread). More importantly, CPDO loss distributions are found to exhibit a wide range of tail risk measures......Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from...... the major rating agencies, based on complex models for the joint transition of ratings and spreads for all names in the underlying portfolio. We propose a parsimonious model for analysing the performance of CPDO strategies using a top-down approach that captures the essential risk factors of the CPDO. Our...
Filament instability under constant loads
Monastra, A. G.; Carusela, M. F.; D’Angelo, M. V.; Bruno, L.
2018-04-01
Buckling of semi-flexible filaments appears in different systems and scales. Some examples are: fibers in geophysical applications, microtubules in the cytoplasm of eukaryotic cells and deformation of polymers freely suspended in a flow. In these examples, instabilities arise when a system’s parameter exceeds a critical value, being the Euler force the most known. However, the complete time evolution and wavelength of buckling processes are not fully understood. In this work we solve analytically the time evolution of a filament under a constant compressive force in the small amplitude approximation. This gives an insight into the variable force scenario in terms of normal modes. The evolution is highly sensitive to the initial configuration and to the magnitude of the compressive load. This model can be a suitable approach to many different real situations.
Evolution of the solar 'constant'
Energy Technology Data Exchange (ETDEWEB)
Newman, M J
1980-06-01
Variations in solar luminosity over geological time are discussed in light of the effect of the solar constant on the evolution of life on earth. Consideration is given to long-term (5 - 7% in a billion years) increases in luminosity due to the conversion of hydrogen into helium in the solar interior, temporary enhancements to solar luminosity due to the accretion of matter from the interstellar medium at intervals on the order of 100 million years, and small-amplitude rapid fluctuations of luminosity due to the stochastic nature of convection on the solar surface. It is noted that encounters with dense interstellar clouds could have had serious consequences for life on earth due to the peaking of the accretion-induced luminosity variation at short wavelengths.
Asympotics with positive cosmological constant
Bonga, Beatrice; Ashtekar, Abhay; Kesavan, Aruna
2014-03-01
Since observations to date imply that our universe has a positive cosmological constant, one needs an extension of the theory of isolated systems and gravitational radiation in full general relativity from the asymptotically flat to asymptotically de Sitter space-times. In current definitions, one mimics the boundary conditions used in asymptotically AdS context to conclude that the asymptotic symmetry group is the de Sitter group. However, these conditions severely restricts radiation and in fact rules out non-zero flux of energy, momentum and angular momentum carried by gravitational waves. Therefore, these formulations of asymptotically de Sitter space-times are uninteresting beyond non-radiative spacetimes. The situation is compared and contrasted with conserved charges and fluxes at null infinity in asymptotically flat space-times.
Le budget total du CERN restera plus ou moins constant
Van der Boon, J E
2002-01-01
The Director of Administration at CERN has written to the paper following an article titled "Licenciements chez les sous-traitants du CERN" : dismissals amongst CERN sub-contractors. As the CERN budget will remain constant and a greater part will be devoted to building the LHC, changes will be made to staffing balances (0.5 page)
The fundamental constants a mystery of physics
Fritzsch, Harald
2009-01-01
The speed of light, the fine structure constant, and Newton's constant of gravity — these are just three among the many physical constants that define our picture of the world. Where do they come from? Are they constant in time and across space? In this book, physicist and author Harald Fritzsch invites the reader to explore the mystery of the fundamental constants of physics in the company of Isaac Newton, Albert Einstein, and a modern-day physicist
International Nuclear Information System (INIS)
Berton, T.R.; Fischer, S.M.; Conti, C.J.; Locniskar, M.F.
1996-01-01
To investigate the effect of various levels of corn oil and coconut oil on ultraviolet (UV) light‐induced skin tumorigenesis and ornithine decarboxylase (ODC) activity, Sencar and SKH‐1 mice were fed one of three 15% (weight) fat semipurified diets containing three ratios of com oil to coconut oil: 1.0%:14.0%, 7.9%:7.1%, and 15.0%:0.0% in Diets A, B, and C, respectively. Groups of 30 Sencar and SKH‐1 mice were fed one of the diets for three weeks before UV irradiation; then both strains were UV irradiated with an initial dose of 90 mJ/cm2. The dose was given three times a week and increased 25% each week. For Sencar mice (irradiated 33 wks for a total dose of 48 J/cm2), tumor incidence reached a maximum of 60%, 60%, and 53% for Diets A, B, and C, respectively, with an overall average of one to two tumors per tumor‐bearing animal. For the SKH‐1 mice (irradiated 29 wks for a total dose of 18 J/cm2), all diet groups reached 100% incidence by 29 weeks, with approximately 12 tumors per tumor‐bearing mouse. No significant effect of dietary corn oil/coconut oil was found for tumor latency, incidence, or yield in either strain. The effect of increasing com oil on epidermal ODC activity in chronically UV‐irradiated Sencar and SKH‐1 mice was assessed Three groups of mice from each strain were fed one of the experimental diets and UV irradiated for six weeks. Sencar mice showed no increase in ODC activity until six weeks of treatment, when the levels of ODC activity in the UV‐irradiated mice fed Diet A were significantly higher than those in mice fed Diet B or Diet C: 1.27, 0.55, and 0.52 nmol/mg protein/hr, respectively. In the SKH‐1 mice, ODC activity was increased by the first week of UV treatment, and by three weeks of treatment a dietary effect was observed: ODC activity was significantly higher in mice fed Diet C (0.70 nmol/mg protein/hr) than in mice fed Diet A (0.18 nmol/mg protein/hr). Although there was no significant effect of dietary corn oil
Directory of Open Access Journals (Sweden)
Leora Halpern Lanz
2015-08-01
Full Text Available The hotel marketing budget, typically amounting to approximately 4-5% of an asset’s total revenue, must remain fluid, so that the marketing director can constantly adapt the marketing tools to meet consumer communications methods and demands. This article suggests how an independent hotel can maximize their marketing budget by using multiple channels and strategies.
Amami, P; Mascia, M M; Franzini, A; Saba, F; Albanese, A
2017-08-01
The study aimed to evaluate safety and efficacy of shifting stimulation settings from constant-voltage (CV) to constant-current (CC) programming in patients with Parkinson's disease (PD) and chronic subthalamic nucleus deep brain stimulation (STN DBS). Twenty PD patients with chronic STN DBS set in CV programming were shifted to CC and followed for 3 months; the other stimulation settings and the medication regimen remained unchanged. Side effects, motor, non-motor, executive functions, and impedance were assessed at baseline and during follow-up. No adverse events were observed at time of shifting or during CC stimulation. Motor and non-motor measures remained unchanged at follow-up despite impedance decreased. Compared to baseline, inhibition processes improved at follow-up. The shifting strategy was well tolerated and the clinical outcome was maintained with no need to adjust stimulation settings or medications notwithstanding a decrease of impedance. Improvement of inhibition processes is a finding which needed further investigation.
Safety provision for nuclear power plants during remaining running time
International Nuclear Information System (INIS)
Rossnagel, Alexander; Hentschel, Anja
2012-01-01
With the phasing-out of the industrial use of nuclear energy for the power generation, the risk of the nuclear power plants has not been eliminated in principle, but only for a limited period of time. Therefore, the remaining nine nuclear power plants must also be used for the remaining ten years according to the state of science and technology. Regulatory authorities must substantiate the safety requirements for each nuclear power plant and enforce these requirements by means of various regulatory measures. The consequences of Fukushima must be included in the assessment of the safety level of nuclear power plants in Germany. In this respect, the regulatory authorities have the important tasks to investigate and assess the security risks as well as to develop instructions and orders.
On use of radial evanescence remain term in kinematic hardening
International Nuclear Information System (INIS)
Geyer, P.
1995-10-01
A fine modelling of the material' behaviour can be necessary to study the mechanical strength of nuclear power plant' components under cyclic loads. Ratchetting is one of the last phenomena for which numerical models have to be improved. We discuss in this paper on use of radial evanescence remain term in kinematic hardening to improve the description of ratchetting in biaxial loading tests. It's well known that Chaboche elastoplastic model with two non linear kinematic hardening variables initially proposed by Armstrong and Frederick, usually over-predicts accumulation of ratchetting strain. Burlet and Cailletaud proposed in 1987 a non linear kinematic rule with a radial evanescence remain term. The two models lead to identical formulation for proportional loadings. In the case of a biaxial loading test (primary+secondary loading), Burlet and Cailletaud model leads to accommodation, when Chaboche one's leads to ratchetting with a constant increment of strain. So we can have an under-estimate with the first model and an over-estimate with the second. An easy method to improve the description of ratchetting is to combine the two kinematic rules. Such an idea is already used by Delobelle in his model. With analytical results in the case of tension-torsion tests, we show in a first part of the paper, the interest of radial evanescence remain term in the non linear kinematic rule to describe ratchetting: we give the conditions to get adaptation, accommodation or ratchetting and the value of the strain increment in the last case. In the second part of the paper, we propose to modify the elastoplastic Chaboche model by coupling the two types of hardening by means of two scalar parameters which can be identified independently on biaxial loading tests. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. We use the experimental results on the austenitic steel 316L at room
Arrhenius Rate: constant volume burn
Energy Technology Data Exchange (ETDEWEB)
Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-12-06
A constant volume burn occurs for an idealized initial state in which a large volume of reactants at rest is suddenly raised to a high temperature and begins to burn. Due to the uniform spatial state, there is no fluid motion and no heat conduction. This reduces the time evolu tion to an ODE for the reaction progress variable. With an Arrhenius reaction rate, two characteristics of thermal ignition are illustrated: induction time and thermal runaway. The Frank-Kamenetskii approximation then leads to a simple expression for the adiabatic induction time. For a first order reaction, the analytic solution is derived and used to illustrate the effect of varying the activation temperature; in particular, on the induction time. In general, the ODE can be solved numerically. This is used to illustrate the effect of varying the reaction order. We note that for a first order reaction, the time evolution of the reaction progress variable has an exponential tail. In contrast, for a reaction order less than one, the reaction completes in a nite time. The reaction order also affects the induction time.
A Kalman-filter estimate of the tidal harmonic constants
International Nuclear Information System (INIS)
Morsetti, R.
1983-01-01
A Kalman-filter estimate of the tidal harmonic constants is proposed in order to take into account their stochastic behaviour. The filter algorithm has been applied to a state-space model of a stochastic system in which the state is defined by the harmonic constants themselves. The results, analysing Trieste sea-level data, have demonstrated that this approach is very suitable for such a purpose, since good estimates and excellent resolution capabilities have been obtained. Furthermore, this method can be very useful also from a practical point of view because real-time computation of the harmonic constants can be developed where an opportune sea-level data acquisition system is available. In conclusion, this paper has emphasized that tidal harmonic constants have to be treated like random variables and, in consequence, new method of analysis can be used
Tuberculosis remains a challenge despite economic growth in Panama.
Tarajia, M; Goodridge, A
2014-03-01
Tuberculosis (TB) is a disease associated with inequality, and wise investment of economic resources is considered critical to its control. Panama has recently secured its status as an upper-middle-income country with robust economic growth. However, the prioritisation of resources for TB control remains a major challenge. In this article, we highlight areas that urgently require action to effectively reduce TB burden to minimal levels. Our conclusions suggest the need for fund allocation and a multidisciplinary approach to ensure prompt laboratory diagnosis, treatment assurance and workforce reinforcement, complemented by applied and operational research, development and innovation.
Positive Cosmological Constant and Quantum Theory
Directory of Open Access Journals (Sweden)
Felix M. Lev
2010-11-01
Full Text Available We argue that quantum theory should proceed not from a spacetime background but from a Lie algebra, which is treated as a symmetry algebra. Then the fact that the cosmological constant is positive means not that the spacetime background is curved but that the de Sitter (dS algebra as the symmetry algebra is more relevant than the Poincare or anti de Sitter ones. The physical interpretation of irreducible representations (IRs of the dS algebra is considerably different from that for the other two algebras. One IR of the dS algebra splits into independent IRs for a particle and its antiparticle only when Poincare approximation works with a high accuracy. Only in this case additive quantum numbers such as electric, baryon and lepton charges are conserved, while at early stages of the Universe they could not be conserved. Another property of IRs of the dS algebra is that only fermions can be elementary and there can be no neutral elementary particles. The cosmological repulsion is a simple kinematical consequence of dS symmetry on quantum level when quasiclassical approximation is valid. Therefore the cosmological constant problem does not exist and there is no need to involve dark energy or other fields for explaining this phenomenon (in agreement with a similar conclusion by Bianchi and Rovelli.
Local Pain Dynamics during Constant Exhaustive Exercise.
Directory of Open Access Journals (Sweden)
Agne Slapsinskaite
Full Text Available The purpose of this study was to delineate the topological dynamics of pain and discomfort during constant exercise performed until volitional exhaustion. Eleven physical education students were tested while cycling and running at a "hard" intensity level (e.g., corresponding to Borg's RPE (6-20 = 15. During the tests, participants reported their discomfort and pain on a body map every 15s. "Time on task" for each participant was divided into five equal non-overlapping temporal windows within which their ratings were considered for analysis. The analyses revealed that the number of body locations with perceived pain and discomfort increased throughout the five temporal windows until reaching the mean (± SE values of 4.2 ± 0.7 and 4.1 ± 0.6 in cycling and running, respectively. The dominant locations included the quadriceps and hamstrings during cycling and quadriceps and chest during running. In conclusion, pain seemed to spread throughout the body during constant cycling and running performed up to volitional exhaustion with differences between cycling and running in the upper body but not in the lower body dynamics.
Lepton Collider Operation with Constant Currents
Wienands, Ulrich
2005-01-01
Traditionally, electron-positron colliders have been operating in a top-off-and-coast fashion with a cycle time depending on the beam life time, typically on the order of an hour. Each top-off involves ramping detector systems in addition to the actual filling time. The loss in accumulated luminosity is typically 20-50%. During the last year, both B-Factories have commissioned a continuous-injection mode of operation in which beam is injected without ramping the detector, thus raising luminosity integration by constant operation at peak luminosity. Constant beam currents reduce thermal drift and trips caused by change in beam loading. To achieve this level of operation, special efforts were made to reduce the injection losses and also to implement special gating procedures in the detectors, minimizing dead time. Bunch-injection control decides which bunch to inject into next while maintaining small charge variation between bunches. Beam collimation can reduce injection noise but also cause an increase in back...
Capacitive Cells for Dielectric Constant Measurement
Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco
2015-01-01
A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.
The Dielectric Constant of Lubrication Oils
National Research Council Canada - National Science Library
Carey, A
1998-01-01
The values of the dielectric constant of simple molecules is discussed first, along with the relationship between the dielectric constant and other physical properties such as boiling point, melting...
Globally Coupled Chaotic Maps with Constant Force
International Nuclear Information System (INIS)
Li Jinghui
2008-01-01
We investigate the motion of the globally coupled maps (logistic map) with a constant force. It is shown that the constant force can cause multi-synchronization for the globally coupled chaotic maps studied by us.
STABILITY CONSTANT OF THE TRISGLYCINATO METAL ...
African Journals Online (AJOL)
DR. AMINU
overall stability constants of the complexes were found to be similar. Keywords: Glycinato, titration ... +. −. = 1 where Ka = dissociation constant of the amino acid. [ ]+. H = concentration of the .... Synthesis and techniques in inorganic chemistry.
Lepton Collider Operation With Constant Currents
International Nuclear Information System (INIS)
Wienands, U.
2006-01-01
Electron-positron colliders have been operating in a top-up-and-coast fashion with a cycle time depending on the beam life time, typically one or more hours. Each top-up involves ramping detector systems in addition to the actual filling time. The loss in accumulated luminosity may be 20-50%. During the last year, both B-Factories have commissioned a continuous-injection mode of operation in which beam is injected without ramping the detector, thus raising luminosity integration by always operating at peak luminosity. Constant beam currents also reduce thermal drift and trips caused by change in beam loading. To achieve this level of operation, special efforts were made to reduce the injection losses and also to implement gating procedures in the detectors, minimizing dead time. Beam collimation can reduce injection noise but also cause an increase in background rates. A challenge can be determining beam lifetime, important to maintain tuning of the beams
Constant mortality and fertility over age in Hydra
DEFF Research Database (Denmark)
Schaible, R.; Scheuerlein, A.; Danko, M. J.
2015-01-01
that 2,256 Hydra from two closely related species in two laboratories in 12 cohorts, with cohort age ranging from 0 to more than 41 y, have extremely low, constant rates of mortality. Fertility rates for Hydra did not systematically decline with advancing age. This falsifies the universality......Senescence, the increase in mortality and decline in fertility with age after maturity, was thought to be inevitable for all multicellular species capable of repeated breeding. Recent theoretical advances and compilations of data suggest that mortality and fertility trajectories can go up or down......, or remain constant with age, but the data are scanty and problematic. Here, we present compelling evidence for constant age-specific death and reproduction rates in Hydra, a basal metazoan, in a set of experiments comprising more than 3.9 million days of observations of individual Hydra. Our data show...
Nuclear fuel market: Supplies remaining stable and secured in the mean range
International Nuclear Information System (INIS)
Braatz, U.; Dibbert, H.J.
1988-01-01
Installation of additional power plant will keep the demand for uranium at a level allowing a constant uranium production during the next few years to come, although production will have to be kept lower than demand, as inventories have to be cut in order to achieve a favourable price structure. Prospects on a mean-term basis show that natural uranium supplies are ensured, at favourable purchaser prices. Concluded contracts for new nuclear power plant indicate a better plant capacity utilization in uranium production to be attainable by the 1990s. Conversion capacity, however, is expected to remain as excessive as presently for quite a long period still, although reprocessing produces increasing amounts of recovered uranium to be converted. The capacity for uranium separative work is favourable for the customers. Existing and projected production facilities already today ensure safe supplies beyond the turn of the millenium, under conditions by far better in terms of long-term competing energy sources. (orig./HP) [de
Search for a Variation of Fundamental Constants
Ubachs, W.
2013-06-01
Since the days of Dirac scientists have speculated about the possibility that the laws of nature, and the fundamental constants appearing in those laws, are not rock-solid and eternal but may be subject to change in time or space. Such a scenario of evolving constants might provide an answer to the deepest puzzle of contemporary science, namely why the conditions in our local Universe allow for extreme complexity: the fine-tuning problem. In the past decade it has been established that spectral lines of atoms and molecules, which can currently be measured at ever-higher accuracies, form an ideal test ground for probing drifting constants. This has brought this subject from the realm of metaphysics to that of experimental science. In particular the spectra of molecules are sensitive for probing a variation of the proton-electron mass ratio μ, either on a cosmological time scale, or on a laboratory time scale. A comparison can be made between spectra of molecular hydrogen observed in the laboratory and at a high redshift (z=2-3), using the Very Large Telescope (Paranal, Chile) and the Keck telescope (Hawaii). This puts a constraint on a varying mass ratio Δμ/μ at the 10^{-5} level. The optical work can also be extended to include CO molecules. Further a novel direction will be discussed: it was discovered that molecules exhibiting hindered internal rotation have spectral lines in the radio-spectrum that are extremely sensitive to a varying proton-electron mass ratio. Such lines in the spectrum of methanol were recently observed with the radio-telescope in Effelsberg (Germany). F. van Weerdenburg, M.T. Murphy, A.L. Malec, L. Kaper, W. Ubachs, Phys. Rev. Lett. 106, 180802 (2011). A. Malec, R. Buning, M.T. Murphy, N. Milutinovic, S.L. Ellison, J.X. Prochaska, L. Kaper, J. Tumlinson, R.F. Carswell, W. Ubachs, Mon. Not. Roy. Astron. Soc. 403, 1541 (2010). E.J. Salumbides, M.L. Niu, J. Bagdonaite, N. de Oliveira, D. Joyeux, L. Nahon, W. Ubachs, Phys. Rev. A 86, 022510
CODATA recommended values of the fundamental constants
International Nuclear Information System (INIS)
Mohr, Peter J.; Taylor, Barry N.
2000-01-01
A review is given of the latest Committee on Data for Science and Technology (CODATA) adjustment of the values of the fundamental constants. The new set of constants, referred to as the 1998 values, replaces the values recommended for international use by CODATA in 1986. The values of the constants, and particularly the Rydberg constant, are of relevance to the calculation of precise atomic spectra. The standard uncertainty (estimated standard deviation) of the new recommended value of the Rydberg constant, which is based on precision frequency metrology and a detailed analysis of the theory, is approximately 1/160 times the uncertainty of the 1986 value. The new set of recommended values as well as a searchable bibliographic database that gives citations to the relevant literature is available on the World Wide Web at physics.nist.gov/constants and physics.nist.gov/constantsbib, respectively
Stability constants of scandium complexes, 1
International Nuclear Information System (INIS)
Itoh, Hisako; Itoh, Naomi; Suzuki, Yasuo
1984-01-01
The stability constants of scandium complexes with some carboxylate ligands were determined potentiometrically at 25.0 and 40.0 0 C and at an ionic strength of 0.10 with potassium nitrate as supporting electrolyte. The constants of the scandium complexes were appreciably greater than those of the corresponding lanthanoid complexes, as expected. The changes in free energy, enthalpy, and entropy for the formation of the scandium complexes were calculated from the stability constants at two temperatures. (author)
Constant exposure technique in industrial radiography
International Nuclear Information System (INIS)
Domanus, J.C.
1983-08-01
The principles and advantages of the constant exposure technique are explained. Choice of exposure factors is analyzed. Film, paper and intensifying screens used throughout the investigation and film and paper processing are described. Exposure technique and the use of image quality indicators are given. Methods of determining of radiographic image quality are presented. Conclusions about the use of constant exposure vs. constant kilovoltage technique are formulated. (author)
Dose rate constants for new dose quantities
International Nuclear Information System (INIS)
Tschurlovits, M.; Daverda, G.; Leitner, A.
1992-01-01
Conceptual changes and new quantities made is necessary to reassess dose rate quantities. Calculations of the dose rate constant were done for air kerma, ambient dose equivalent and directional dose equivalent. The number of radionuclides is more than 200. The threshold energy is selected as 20 keV for the dose equivalent constants. The dose rate constant for the photon equivalent dose as used mainly in German speaking countries as a temporary quantity is also included. (Author)
A natural cosmological constant from chameleons
International Nuclear Information System (INIS)
Nastase, Horatiu; Weltman, Amanda
2015-01-01
We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero) and the coincidence problem (why Λ is comparable to the matter density now)
A natural cosmological constant from chameleons
Directory of Open Access Journals (Sweden)
Horatiu Nastase
2015-07-01
Full Text Available We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero and the coincidence problem (why Λ is comparable to the matter density now.
A natural cosmological constant from chameleons
Energy Technology Data Exchange (ETDEWEB)
Nastase, Horatiu, E-mail: nastase@ift.unesp.br [Instituto de Física Teórica, UNESP-Universidade Estadual Paulista, R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Weltman, Amanda, E-mail: amanda.weltman@uct.ac.za [Astrophysics, Cosmology & Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa)
2015-07-30
We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero) and the coincidence problem (why Λ is comparable to the matter density now)
Cisneros, Luis Natera; Reiriz, Juan Sarasquete
2017-04-01
To determine the prevalence of remaining horizontal instability in high-grade acromioclavicular joint (ACJ) injuries surgically managed by means of four different surgical strategies and to assess its relation to the clinical outcomes and the quality of life. In this multicentric non-randomized retrospective study, 53 patients with high-grade ACJ injuries surgically managed (by means of open or arthroscopic surgery) were clinically and radiographically assessed at 24 months or more after shoulder surgery. The presence of post-surgical remaining horizontal instability was evaluated by means of Alexander or axillary X-ray views. The study population was divided into two groups: patients with evidence of post-surgical remaining horizontal instability and patients without evidence of post-surgical remaining horizontal instability at the last follow-up visit. The relationship between remaining horizontal instability and the quality-of-life questionnaires was analyzed. 18.87% (10/53) of the Alexander or axillary X-rays views showed post-surgical remaining horizontal instability at the last follow-up visit (INSTAB-group). Results of the questionnaires were: (1) physical SF36 score (INSTAB-group 57.02 ± 3.17 and NO-INSTAB-group 57.66 ± 3.30, p = 0.583); (2) mental SF36 score (INSTAB-group 53.95 ± 3.98 and NO-INSTAB-group 55.71 ± 3.30, p = 0.150); (3) NRS for pain (INSTAB-group 1.30 ± 1.49 and NO-INSTAB-group 0.83 ± 1.08, p = 0.260); (4) DASH questionnaire (INSTAB-group 5.27 ± 5.42 and NO-INSTAB-group 3.06 ± 2.30, p = 0.049); (5) Constant score (INSTAB-group 93.4 ± 3.5 and NO-INSTAB-group 94.83 ± 4.3, p = 0.333); and Global satisfaction (INSTAB-group 8.7 ± 0.95 and NO-INSTAB-group 8.64 ± 1.03, p = 0.874). Independently of the type of procedure, post-surgical remaining horizontal instability was present in almost one-fifth of the patients, and this group of patients showed a significantly worse DASH score. The
Remaining lifetime modeling using State-of-Health estimation
Beganovic, Nejra; Söffker, Dirk
2017-08-01
has lower degrees of freedom. Both approaches rely on previously developed lifetime models each of them corresponding to predefined SoH. Concerning first approach, model selection is aided by state-machine-based algorithm. In the second approach, model selection conditioned by tracking an exceedance of predefined thresholds is concerned. The approach is applied to data generated from tribological systems. By calculating Root Squared Error (RSE), Mean Squared Error (MSE), and Absolute Error (ABE) the accuracy of proposed models/approaches is discussed along with related advantages and disadvantages. Verification of the approach is done using cross-fold validation, exchanging training and test data. It can be stated that the newly introduced approach based on data (denoted as data-based or data-driven) parametric models can be easily established providing detailed information about remaining useful/consumed lifetime valid for systems with constant load but stochastically occurred damage.
Directory of Open Access Journals (Sweden)
Jan Moestedt
2015-01-01
Full Text Available To optimize commercial-scale biogas production, it is important to evaluate the performance of each microbial step in the anaerobic process. Hydrolysis and methanogenesis are usually the rate-limiting steps during digestion of organic waste and by-products. By measuring biogas production and methane concentrations on-line in a semi-continuously fed reactor, gas kinetics can be evaluated. In this study, the rate constants of the fermentative hydrolysis step (kc and the methanogenesis step (km were determined and evaluated in a continuously stirred tank laboratory-scale reactor treating food and slaughterhouse waste and glycerin. A process additive containing Fe2+, Co2+ and Ni2+ was supplied until day 89, after which Ni2+ was omitted. The omission resulted in a rapid decline in the methanogenesis rate constant (km to 70% of the level observed when Ni2+ was present, while kc remained unaffected. This suggests that Ni2+ mainly affects the methanogenic rather than the hydrolytic microorganisms in the system. However, no effect was initially observed when using conventional process monitoring parameters such as biogas yield and volatile fatty acid concentration. Hence, formation rate constants can reveal additional information on process performance and km can be used as a complement to conventional process monitoring tools for semi-continuously fed anaerobic digesters.
Extraction of elementary rate constants from global network analysis of E. coli central metabolism
Directory of Open Access Journals (Sweden)
Broderick Gordon
2008-05-01
Full Text Available Abstract Background As computational performance steadily increases, so does interest in extending one-particle-per-molecule models to larger physiological problems. Such models however require elementary rate constants to calculate time-dependent rate coefficients under physiological conditions. Unfortunately, even when in vivo kinetic data is available, it is often in the form of aggregated rate laws (ARL that do not specify the required elementary rate constants corresponding to mass-action rate laws (MRL. There is therefore a need to develop a method which is capable of automatically transforming ARL kinetic information into more detailed MRL rate constants. Results By incorporating proteomic data related to enzyme abundance into an MRL modelling framework, here we present an efficient method operating at a global network level for extracting elementary rate constants from experiment-based aggregated rate law (ARL models. The method combines two techniques that can be used to overcome the difficult properties in parameterization. The first, a hybrid MRL/ARL modelling technique, is used to divide the parameter estimation problem into sub-problems, so that the parameters of the mass action rate laws for each enzyme are estimated in separate steps. This reduces the number of parameters that have to be optimized simultaneously. The second, a hybrid algebraic-numerical simulation and optimization approach, is used to render some rate constants identifiable, as well as to greatly narrow the bounds of the other rate constants that remain unidentifiable. This is done by incorporating equality constraints derived from the King-Altman and Cleland method into the simulated annealing algorithm. We apply these two techniques to estimate the rate constants of a model of E. coli glycolytic pathways. The simulation and statistical results show that our innovative method performs well in dealing with the issues of high computation cost, stiffness, local
Extraction of elementary rate constants from global network analysis of E. coli central metabolism
Zhao, Jiao; Ridgway, Douglas; Broderick, Gordon; Kovalenko, Andriy; Ellison, Michael
2008-01-01
Background As computational performance steadily increases, so does interest in extending one-particle-per-molecule models to larger physiological problems. Such models however require elementary rate constants to calculate time-dependent rate coefficients under physiological conditions. Unfortunately, even when in vivo kinetic data is available, it is often in the form of aggregated rate laws (ARL) that do not specify the required elementary rate constants corresponding to mass-action rate laws (MRL). There is therefore a need to develop a method which is capable of automatically transforming ARL kinetic information into more detailed MRL rate constants. Results By incorporating proteomic data related to enzyme abundance into an MRL modelling framework, here we present an efficient method operating at a global network level for extracting elementary rate constants from experiment-based aggregated rate law (ARL) models. The method combines two techniques that can be used to overcome the difficult properties in parameterization. The first, a hybrid MRL/ARL modelling technique, is used to divide the parameter estimation problem into sub-problems, so that the parameters of the mass action rate laws for each enzyme are estimated in separate steps. This reduces the number of parameters that have to be optimized simultaneously. The second, a hybrid algebraic-numerical simulation and optimization approach, is used to render some rate constants identifiable, as well as to greatly narrow the bounds of the other rate constants that remain unidentifiable. This is done by incorporating equality constraints derived from the King-Altman and Cleland method into the simulated annealing algorithm. We apply these two techniques to estimate the rate constants of a model of E. coli glycolytic pathways. The simulation and statistical results show that our innovative method performs well in dealing with the issues of high computation cost, stiffness, local minima and uncertainty
Spin-rotation and NMR shielding constants in HCl
Energy Technology Data Exchange (ETDEWEB)
Jaszuński, Michał, E-mail: michal.jaszunski@icho.edu.pl [Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warszawa, Kasprzaka 44 (Poland); Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø—The Arctic University of Norway, N-9037 Tromsø (Norway); Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz [Laboratory of NMR Spectroscopy, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)
2013-12-21
The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of {sup 1}H{sup 35}Cl are C{sub Cl} = −53.914 kHz and C{sub H} = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values.
Spin-rotation and NMR shielding constants in HCl
International Nuclear Information System (INIS)
Jaszuński, Michał; Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth; Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz
2013-01-01
The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of 1 H 35 Cl are C Cl = −53.914 kHz and C H = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values
Equilibrium-constant expressions for aqueous plutonium
International Nuclear Information System (INIS)
Silver, G.L.
2010-01-01
Equilibrium-constant expressions for Pu disproportionation reactions traditionally contain three or four terms representing the concentrations or fractions of the oxidation states. The expressions can be rewritten so that one of the oxidation states is replaced by a term containing the oxidation number of the plutonium. Experimental estimations of the numerical values of the constants can then be checked in several ways. (author)
A null test of the cosmological constant
International Nuclear Information System (INIS)
Chiba, Takeshi; Nakamura, Takashi
2007-01-01
We provide a consistency relation between cosmological observables in general relativity with the cosmological constant. Breaking of this relation at any redshift would imply the breakdown of the hypothesis of the cosmological constant as an explanation of the current acceleration of the universe. (author)
A stringy nature needs just two constants
International Nuclear Information System (INIS)
Veneziano, G.
1986-01-01
Dual string theories of everything, being purely geometrical, contain only two fundamental constants: c, for relativistic invariance, and a length lambda, for quantization. Planck's and Newton's constants appear only through Planck's length, a ''calculable'' fraction of lambda. Only the existence of a light sector breaks a ''reciprocity'' principle and unification at lambda, which is also the theory's cut-off
On special relativity with cosmological constant
International Nuclear Information System (INIS)
Guo Hanying; Huang Chaoguang; Xu Zhan; Zhou Bin
2004-01-01
Based on the principle of relativity and the postulate of invariant speed and length, we propose the theory of special relativity with cosmological constant SRc,R, in which the cosmological constant is linked with the invariant length. Its relation with the doubly special relativity is briefly mentioned
DETERMINATION OF STABILITY CONSTANTS OF MANGANESE (II ...
African Journals Online (AJOL)
DR. AMINU
Keywords: Amino acids, dissociation constant, potentiometry, stability constant. INTRODUCTION. Acids – base titration involves the gradual addition or removal of protons for example using the deprotic form of glycine. The plot has two distinct stages corresponding to the deprotonation of the two different groups on glycine.
Shapley Value for Constant-sum Games
Khmelnitskaya, A.B.
2002-01-01
It is proved that Young's axiomatization for the Shapley value by marginalism, efficiency, and symmetry is still valid for the Shapley value defined on the class of nonnegative constant-sum games and on the entire class of constant-sum games as well. To support an interest to study the class of
Constant Width Planar Computation Characterizes ACC0
DEFF Research Database (Denmark)
Hansen, Kristoffer Arnsfelt
2006-01-01
We obtain a characterization of ACC0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...
Experimental Determination of the Avogadro Constant
Indian Academy of Sciences (India)
mental physical constant such as charge of an electron or the. Boltzmann constant ... ideas was that the number of particles or molecules in a gas of given volume could not ... knowledge of at least one property of a single molecule. Loschmidt ...
The time constant of the somatogravic illusion.
Correia Grácio, B J; de Winkel, K N; Groen, E L; Wentink, M; Bos, J E
2013-02-01
Without visual feedback, humans perceive tilt when experiencing a sustained linear acceleration. This tilt illusion is commonly referred to as the somatogravic illusion. Although the physiological basis of the illusion seems to be well understood, the dynamic behavior is still subject to discussion. In this study, the dynamic behavior of the illusion was measured experimentally for three motion profiles with different frequency content. Subjects were exposed to pure centripetal accelerations in the lateral direction and were asked to indicate their tilt percept by means of a joystick. Variable-radius centrifugation during constant angular rotation was used to generate these motion profiles. Two self-motion perception models were fitted to the experimental data and were used to obtain the time constant of the somatogravic illusion. Results showed that the time constant of the somatogravic illusion was on the order of two seconds, in contrast to the higher time constant found in fixed-radius centrifugation studies. Furthermore, the time constant was significantly affected by the frequency content of the motion profiles. Motion profiles with higher frequency content revealed shorter time constants which cannot be explained by self-motion perception models that assume a fixed time constant. Therefore, these models need to be improved with a mechanism that deals with this variable time constant. Apart from the fundamental importance, these results also have practical consequences for the simulation of sustained accelerations in motion simulators.
Graviton fluctuations erase the cosmological constant
Wetterich, C.
2017-10-01
Graviton fluctuations induce strong non-perturbative infrared renormalization effects for the cosmological constant. The functional renormalization flow drives a positive cosmological constant towards zero, solving the cosmological constant problem without the need to tune parameters. We propose a simple computation of the graviton contribution to the flow of the effective potential for scalar fields. Within variable gravity, with effective Planck mass proportional to the scalar field, we find that the potential increases asymptotically at most quadratically with the scalar field. The solutions of the derived cosmological equations lead to an asymptotically vanishing cosmological "constant" in the infinite future, providing for dynamical dark energy in the present cosmological epoch. Beyond a solution of the cosmological constant problem, our simplified computation also entails a sizeable positive graviton-induced anomalous dimension for the quartic Higgs coupling in the ultraviolet regime, substantiating the successful prediction of the Higgs boson mass within the asymptotic safety scenario for quantum gravity.
Solar constant values for estimating solar radiation
International Nuclear Information System (INIS)
Li, Huashan; Lian, Yongwang; Wang, Xianlong; Ma, Weibin; Zhao, Liang
2011-01-01
There are many solar constant values given and adopted by researchers, leading to confusion in estimating solar radiation. In this study, some solar constant values collected from literature for estimating solar radiation with the Angstroem-Prescott correlation are tested in China using the measured data between 1971 and 2000. According to the ranking method based on the t-statistic, a strategy to select the best solar constant value for estimating the monthly average daily global solar radiation with the Angstroem-Prescott correlation is proposed. -- Research highlights: → The effect of the solar constant on estimating solar radiation is investigated. → The investigation covers a diverse range of climate and geography in China. → A strategy to select the best solar constant for estimating radiation is proposed.
Galvanic Cells and the Determination of Equilibrium Constants
Brosmer, Jonathan L.; Peters, Dennis G.
2012-01-01
Readily assembled mini-galvanic cells can be employed to compare their observed voltages with those predicted from the Nernst equation and to determine solubility products for silver halides and overall formation constants for metal-ammonia complexes. Results obtained by students in both an honors-level first-year course in general chemistry and…
Decay constants in soft wall AdS/QCD revisited
Directory of Open Access Journals (Sweden)
Nelson R.F. Braga
2016-12-01
We show here that a modified framework of soft wall AdS/QCD involving an additional dimensionfull parameter, associated with an ultraviolet energy scale, provides decay constants decreasing with radial excitation level. In this version of the soft wall model the two point function of gauge theory operators is calculated at a finite position of the anti-de Sitter space radial coordinate.
Premortal data in the process of skeletal remains identification
Directory of Open Access Journals (Sweden)
Marinković Nadica
2012-01-01
Full Text Available Background/Aim. The basic task of a forensic examiner during the exhumation of mass graves or in mass accidents is to establish identity of a person. The results obtained through these procedures depend on the level of perceptibility of post mortal changes and they are compared with premortal data obtained from family members of those missing or killed. Experience with exhumations has shown significant differences between the results obtained through exhumation and the premortal data. The aim of the study was to suggest the existance of the difference between premortal data and the results obtained by exhumation regarding the some parameters, as well as to direct premortal data colection to the specific skeletal forms. Methods. We performed comparative analysis of the results of exhumation of skeletal remains in a mass grave and the premortal data concerning the identified persons. The least number of individuals in this mass grave was calculated according to the upper parts of the right femur and it helped in calculating the smallest number of individuals in mass graves to be 48. A total of 27 persons were identified. Sex was determined by metrics and morphology of the pelvis. Personal age in the moment of death was determined by morphology features of groin symphisis and morphology of sternal edge of ribs and other parts of scelets observations. The hight was calculated as average results of length of long bones and Rollet coefficients. Results. There was a complete match in terms of sex and age matched within an interval that could be established based on the skeletal remains. All the other parameters were different, however, which made identification significantly more difficult. Conclusion. The premortal data is an important element of identification process and it should be obtained by the forensic doctor and directed towards more detailed examination of the skeletal system.
Atomic fine structure in a space of constant curvature
International Nuclear Information System (INIS)
Bessis, N.; Bessis, G.; Shamseddine, R.
1982-01-01
As a contribution to a tentative formulation of atomic physics in a curved space, the determination of atomic fine structure energies in a space of constant curvature is investigated. Starting from the Dirac equation in a curved space-time, the analogue of the Pauli equation in a general coordinate system is derived. The theoretical curvature induced shifts and splittings of the fine structure energy levels are put in evidence and examined for the particular case of the hydrogenic n=2 levels. (author)
AIDS, individual behaviour and the unexplained remaining variation.
Katz, Alison
2002-01-01
From the start of the AIDS pandemic, individual behaviour has been put forward, implicitly or explicitly, as the main explanatory concept for understanding the epidemiology of HIV infection and in particular for the rapid spread and high prevalence in sub-Saharan Africa. This has had enormous implications for the international response to AIDS and has heavily influenced public health policy and strategy and the design of prevention and care interventions at national, community and individual level. It is argued that individual behaviour alone cannot possibly account for the enormous variation in HIV prevalence between population groups, countries and regions and that the unexplained remaining variation has been neglected by the international AIDS community. Biological vulnerability to HIV due to seriously deficient immune systems has been ignored as a determinant of the high levels of infection in certain populations. This is in sharp contrast to well proven public health approaches to other infectious diseases. In particular, it is argued that poor nutrition and co-infection with the myriad of other diseases of poverty including tuberculosis, malaria, leishmaniasis and parasitic infections, have been neglected as root causes of susceptibility, infectiousness and high rates of transmission of HIV at the level of populations. Vulnerability in terms of non-biological factors such as labour migration, prostitution, exchange of sex for survival, population movements due to war and violence, has received some attention but the solutions proposed to these problems are also inappropriately focused on individual behaviour and suffer from the same neglect of economic and political root causes. As the foundation for the international community's response to the AIDS pandemic, explanations of HIV/AIDS epidemiology in terms of individual behaviour are not only grossly inadequate, they are highly stigmatising and may in some cases, be racist. They have diverted attention from
On the constants for some Sobolev imbeddings
Directory of Open Access Journals (Sweden)
Pizzocchero Livio
2001-01-01
Full Text Available We consider the imbedding inequality is the Sobolev space (or Bessel potential space of type and (integer or fractional order . We write down upper bounds for the constants , using an argument previously applied in the literature in particular cases. We prove that the upper bounds computed in this way are in fact the sharp constants if , , and exhibit the maximising functions. Furthermore, using convenient trial functions, we derive lower bounds on for in many cases these are close to the previous upper bounds, as illustrated by a number of examples, thus characterizing the sharp constants with little uncertainty.
On the constant-roll inflation
Yi, Zhu; Gong, Yungui
2018-03-01
The primordial power spectra of scalar and tensor perturbations during slow-roll inflation are usually calculated with the method of Bessel function approximation. For constant-roll or ultra slow-roll inflation, the method of Bessel function approximation may be invalid. We compare the numerical results with the analytical results derived from the Bessel function approximation, and we find that they differ significantly on super-horizon scales if the constant slow-roll parameter ηH is not small. More accurate method is needed for calculating the primordial power spectrum for constant-roll inflation.
Scalar-tensor cosmology with cosmological constant
International Nuclear Information System (INIS)
Maslanka, K.
1983-01-01
The equations of scalar-tensor theory of gravitation with cosmological constant in the case of homogeneous and isotropic cosmological model can be reduced to dynamical system of three differential equations with unknown functions H=R/R, THETA=phi/phi, S=e/phi. When new variables are introduced the system becomes more symmetrical and cosmological solutions R(t), phi(t), e(t) are found. It is shown that when cosmological constant is introduced large class of solutions which depend also on Dicke-Brans parameter can be obtained. Investigations of these solutions give general limits for cosmological constant and mean density of matter in plane model. (author)
Cosmological constant and advanced gravitational wave detectors
International Nuclear Information System (INIS)
Wang, Y.; Turner, E.L.
1997-01-01
Interferometric gravitational wave detectors could measure the frequency sweep of a binary inspiral (characterized by its chirp mass) to high accuracy. The observed chirp mass is the intrinsic chirp mass of the binary source multiplied by (1+z), where z is the redshift of the source. Assuming a nonzero cosmological constant, we compute the expected redshift distribution of observed events for an advanced LIGO detector. We find that the redshift distribution has a robust and sizable dependence on the cosmological constant; the data from advanced LIGO detectors could provide an independent measurement of the cosmological constant. copyright 1997 The American Physical Society
Constant strength fuel-fuel cell
International Nuclear Information System (INIS)
Vaseen, V.A.
1980-01-01
A fuel cell is an electrochemical apparatus composed of both a nonconsumable anode and cathode; and electrolyte, fuel oxidant and controls. This invention guarantees the constant transfer of hydrogen atoms and their respective electrons, thus a constant flow of power by submergence of the negative electrode in a constant strength hydrogen furnishing fuel; when said fuel is an aqueous absorbed hydrocarbon, such as and similar to ethanol or methnol. The objective is accomplished by recirculation of the liquid fuel, as depleted in the cell through specific type membranes which pass water molecules and reject the fuel molecules; thus concentrating them for recycle use
Reactor group constants and benchmark test
Energy Technology Data Exchange (ETDEWEB)
Takano, Hideki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
2001-08-01
The evaluated nuclear data files such as JENDL, ENDF/B-VI and JEF-2 are validated by analyzing critical mock-up experiments for various type reactors and assessing applicability for nuclear characteristics such as criticality, reaction rates, reactivities, etc. This is called Benchmark Testing. In the nuclear calculations, the diffusion and transport codes use the group constant library which is generated by processing the nuclear data files. In this paper, the calculation methods of the reactor group constants and benchmark test are described. Finally, a new group constants scheme is proposed. (author)
Clinical Course of Homozygous Hemoglobin Constant Spring in Pediatric Patients.
Komvilaisak, Patcharee; Jetsrisuparb, Arunee; Fucharoen, Goonnapa; Komwilaisak, Ratana; Jirapradittha, Junya; Kiatchoosakun, Pakaphan
2018-04-17
Hemoglobin (Hb) Constant Spring is an alpha-globin gene variant due to a mutation of the stop codon resulting in the elongation of the encoded polypeptide from 141 to 172 amino acid residues. Patients with homozygous Hb Constant Spring are usually mildly anemic. We retrospectively describe clinical manifestations, diagnosis, laboratory investigations, treatment, and associated findings in pediatric patients with homozygous Hb Constant Spring followed-up at Srinagarind Hospital. Sixteen pediatric cases (5 males and 11 females) were diagnosed in utero (N=6) or postnatal (n=10). Eleven cases were diagnosed with homozygous Hb Constant Spring, 4 with homozygous Hb Constant Spring with heterozygous Hb E, and 1 with homozygous Hb Constant Spring with homozygous Hb E. Three cases were delivered preterm. Six patients had low birth weights. Clinical manifestations included fetal anemia in 6 cases, hepatomegaly in 1 case, hepatosplenomegaly in 2 cases, splenomegaly in 1 case. Twelve cases exhibited early neonatal jaundice, 9 of which required phototherapy. Six cases received red cell transfusions; 1 (3), >1 (3). After the first few months of life, almost all patients had mild microcytic hypochromic anemia and an increased reticulocyte count with a wide red cell distribution (RDW), but no longer required red cell transfusion. At 1 to 2 years of age, some patients still had mild microcytic hypochromic anemia and some had normocytic hypochromic anemia with Hb around 10 g/dL, increased reticulocyte count and wide RDW. Associated findings included hypothyroidism (2), congenital heart diseases (4), genitourinary abnormalities (3), gastrointestinal abnormalities (2), and developmental delay (1). Pediatric patients with homozygous Hb Constant Spring developed severe anemia in utero and up to the age of 2 to 3 months postnatal, requiring blood transfusions. Subsequently, their anemia was mild with no evidence of hepatosplenomegaly. Their Hb level was above 9 g/dL with hypochromic
Berryman, James G; Nakagawa, Seiji
2010-02-01
Poroelastic analysis has traditionally focused on the relationship between dry and drained constants, which are assumed known, and the saturated or undrained constants, which are assumed unknown. However, there are many applications in this field of study for which the main measurements can only be made on the saturated/undrained system, and then it is uncertain what the effects of the fluids were on the system, since the drained constants remain a mystery. The work presented here shows how to deduce drained constants from undrained constants for anisotropic systems having symmetries ranging from isotropic to orthotropic. Laboratory ultrasound data are then inverted for the drained constants in three granular packings: one of glass beads, and two others for distinct types of more or less angular sand grain packings. Experiments were performed under uniaxial stress, which resulted in hexagonal (transversely isotropic) symmetry of the poroelastic response. One important conclusion from the general analysis is that the drained constants are uniquely related to the undrained constants, assuming that porosity, grain bulk modulus, and pore fluid bulk modulus are already known. Since the resulting system of equations for all the drained constants is linear, measurement error in undrained constants also propagates linearly into the computed drained constants.
Energy Technology Data Exchange (ETDEWEB)
Berryman, J.G.; Nakagawa, S.
2009-11-20
Poroelastic analysis has traditionally focused on the relationship between dry or drained constants which are assumed known and the saturated or undrained constants which are assumed unknown. However, there are many applications in this field of study for which the main measurements can only be made on the saturated/undrained system, and then it is uncertain what the eects of the uids were on the system, since the drained constants remain a mystery. The work presented here shows how to deduce drained constants from undrained constants for anisotropic systems having symmetries ranging from isotropic to orthotropic. Laboratory ultrasound data are then inverted for the drained constants in three granular packings: one of glass beads, and two others for distinct types of more or less angular sand grain packings. Experiments were performed under uniaxial stress, which resulted in hexagonal (transversely isotropic) symmetry of the poroelastic response. One important conclusion from the general analysis is that the drained constants are uniquely related to the undrained constants, assuming that porosity, grain bulk modulus, and pore uid bulk modulus are already known. Since the resulting system of equations for all the drained constants is linear, measurement error in undrained constants also propagates linearly into the computed drained constants.
Spot market activity remains weak as prices continue to fall
International Nuclear Information System (INIS)
Anon.
1996-01-01
A summary of financial data for the uranium spot market in November 1996 is provided. Price ranges for the restricted and unrestricted markets, conversion, and separative work are listed, and total market volume and new contracts are noted. Transactions made are briefly described. Deals made and pending in the spot concentrates, medium and long-term, conversion, and markets are listed for U.S. and non-U.S. buyers. Spot market activity increased in November with just over 1.0 million lbs of U3O8 equivalent being transacted compared to October's total of 530,000 lbs of U3O8 equivalent. The restricted uranium spot market price range slipped from $15.50-$15.70/lb U3O8 last month to $14.85/lb - $15.25/lb U3O8 this month. The unrestricted uranium spot market price range also slipped to $14.85/lb - $15.00/lb this month from $15.00/lb - $15.45/lb in October. Spot prices for conversion and separative work units remained at their October levels
Mitochondrial fatty acid oxidation defects--remaining challenges
DEFF Research Database (Denmark)
Gregersen, Niels; Andresen, Brage S; Pedersen, Christina B
2008-01-01
Mitochondrial fatty acid oxidation defects have been recognized since the early 1970s. The discovery rate has been rather constant, with 3-4 'new' disorders identified every decade and with the most recent example, ACAD9 deficiency, reported in 2007. In this presentation we will focus on three...
Pearson, A.; Pizzuto, J. E.
2015-12-01
Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.
Relationship between electrophilicity index, Hammett constant and ...
Indian Academy of Sciences (India)
Unknown
Inter-relationships between the electrophilicity index (ω), Hammett constant (óp) and nucleus- independent chemical ... cess of DFT is that it provides simple working equa- tions to elucidate ... compasses both the ability of an electrophile to ac-.
Canonoid transformations and constants of motion
International Nuclear Information System (INIS)
Negri, L.J.; Oliveira, L.C.; Teixeira, J.M.
1986-01-01
The necessary and sufficient conditions for a canonoid transformation with respect to a given Hamiltonian are obtained in terms of the Lagrange brackets of the trasformation. The relation of these conditions with the constants of motion is discussed. (Author) [pt
An improved dosimeter having constant flow pump
International Nuclear Information System (INIS)
Baker, W.B.
1980-01-01
A dosemeter designed for individual use which can be used to monitor toxic radon gas and toxic related products of radon gas in mines and which incorporates a constant air stream flowing through the dosimeter is described. (U.K.)
New perspectives on constant-roll inflation
Cicciarella, Francesco; Mabillard, Joel; Pieroni, Mauro
2018-01-01
We study constant-roll inflation using the β-function formalism. We show that the constant rate of the inflaton roll is translated into a first order differential equation for the β-function which can be solved easily. The solutions to this equation correspond to the usual constant-roll models. We then construct, by perturbing these exact solutions, more general classes of models that satisfy the constant-roll equation asymptotically. In the case of an asymptotic power law solution, these corrections naturally provide an end to the inflationary phase. Interestingly, while from a theoretical point of view (in particular in terms of the holographic interpretation) these models are intrinsically different from standard slow-roll inflation, they may have phenomenological predictions in good agreement with present cosmological data.
Hydrolysis and formation constants at 250C
International Nuclear Information System (INIS)
Phillips, S.L.
1982-05-01
A database consisting of hydrolysis and formation constants for about 20 metals associated with the disposal of nuclear waste is given. Complexing ligands for the various ionic species of these metals include OH, F, Cl, SO 4 , PO 4 and CO 3 . Table 1 consists of tabulated calculated and experimental values of log K/sub xy/, mainly at 25 0 C and various ionic strengths together with references to the origin of the data. Table 2 consists of a column of recommended stability constants at 25 0 C and zero ionic strength tabulated in the column headed log K/sub xy/(0); other columns contain coefficients for an extended Debye-Huckel equation to permit calculations of stability constants up to 3 ionic strength, and up to 0.7 ionic strength using the Davies equation. Selected stability constants calculated with these coefficients for various ionic strengths agree to an average of +- 2% when compared with published experimental and calculated values
Wormholes and the cosmological constant problem.
Klebanov, I.
The author reviews the cosmological constant problem and the recently proposed wormhole mechanism for its solution. Summation over wormholes in the Euclidean path integral for gravity turns all the coupling parameters into dynamical variables, sampled from a probability distribution. A formal saddle point analysis results in a distribution with a sharp peak at the cosmological constant equal to zero, which appears to solve the cosmological constant problem. He discusses the instabilities of the gravitational Euclidean path integral and the difficulties with its interpretation. He presents an alternate formalism for baby universes, based on the "third quantization" of the Wheeler-De Witt equation. This approach is analyzed in a minisuperspace model for quantum gravity, where it reduces to simple quantum mechanics. Once again, the coupling parameters become dynamical. Unfortunately, the a priori probability distribution for the cosmological constant and other parameters is typically a smooth function, with no sharp peaks.
Cauchy horizon stability and mass inflation with a cosmological constant
International Nuclear Information System (INIS)
Costa, João L; Girão, Pedro M; Natário, José; Silva, Jorge Drumond
2015-01-01
Motivated by the strong cosmic censorship conjecture, we consider the Einstein- Maxwell-scalar field system with a cosmological constant Λ (of any sign), under spherical symmetry, for characteristic initial conditions, with outgoing data prescribed by a (complete) subextremal Reissner-Nordstrom black hole event horizon. We study the structure of the future maximal (globally hyperbolic) development, analyze the mass inflation scenarios, identifying, in particular, large choices of parameters for which the Hawking mass remains bounded, and study the existence of regular extensions. We also discuss why our results, although valid for all signs of Λ, only provide evidence for the failure of strong cosmic censorship in the case of a positive cosmological constant. (paper)
Shigematsu, Hideki; Kawaguchi, Masahiko; Hayashi, Hironobu; Takatani, Tsunenori; Iwata, Eiichiro; Tanaka, Masato; Okuda, Akinori; Morimoto, Yasuhiko; Masuda, Keisuke; Tanaka, Yuu; Tanaka, Yasuhito
2017-10-01
During spine surgery, the spinal cord is electrophysiologically monitored via transcranial electrical stimulation of motor-evoked potentials (TES-MEPs) to prevent injury. Transcranial electrical stimulation of motor-evoked potential involves the use of either constant-current or constant-voltage stimulation; however, there are few comparative data available regarding their ability to adequately elicit compound motor action potentials. We hypothesized that the success rates of TES-MEP recordings would be similar between constant-current and constant-voltage stimulations in patients undergoing spine surgery. The objective of this study was to compare the success rates of TES-MEP recordings between constant-current and constant-voltage stimulation. This is a prospective, within-subject study. Data from 100 patients undergoing spinal surgery at the cervical, thoracic, or lumbar level were analyzed. The success rates of the TES-MEP recordings from each muscle were examined. Transcranial electrical stimulation with constant-current and constant-voltage stimulations at the C3 and C4 electrode positions (international "10-20" system) was applied to each patient. Compound muscle action potentials were bilaterally recorded from the abductor pollicis brevis (APB), deltoid (Del), abductor hallucis (AH), tibialis anterior (TA), gastrocnemius (GC), and quadriceps (Quad) muscles. The success rates of the TES-MEP recordings from the right Del, right APB, bilateral Quad, right TA, right GC, and bilateral AH muscles were significantly higher using constant-voltage stimulation than those using constant-current stimulation. The overall success rates with constant-voltage and constant-current stimulations were 86.3% and 68.8%, respectively (risk ratio 1.25 [95% confidence interval: 1.20-1.31]). The success rates of TES-MEP recordings were higher using constant-voltage stimulation compared with constant-current stimulation in patients undergoing spinal surgery. Copyright © 2017
Building evolutionary architectures support constant change
Ford, Neal; Kua, Patrick
2017-01-01
The software development ecosystem is constantly changing, providing a constant stream of new tools, frameworks, techniques, and paradigms. Over the past few years, incremental developments in core engineering practices for software development have created the foundations for rethinking how architecture changes over time, along with ways to protect important architectural characteristics as it evolves. This practical guide ties those parts together with a new way to think about architecture and time.
Nuclei quadrupole coupling constants in diatomic molecule
International Nuclear Information System (INIS)
Ivanov, A.I.; Rebane, T.K.
1993-01-01
An approximate relationship between the constants of quadrupole interaction of nuclei in a two-atom molecule is found. It enabled to establish proportionality of oscillatory-rotation corrections to these constants for both nuclei in the molecule. Similar results were obtained for the factors of electrical dipole-quadrupole screening of nuclei. Applicability of these relationships is proven by the example of lithium deuteride molecule. 4 refs., 1 tab
Parametrised Constants and Replication for Spatial Mobility
DEFF Research Database (Denmark)
Hüttel, Hans; Haagensen, Bjørn
2009-01-01
Parametrised replication and replication are common ways of expressing infinite computation in process calculi. While parametrised constants can be encoded using replication in the π-calculus, this changes in the presence of spatial mobility as found in e.g. the distributed π- calculus...... of the distributed π-calculus with parametrised constants and replication are incomparable. On the other hand, we shall see that there exists a simple encoding of recursion in mobile ambients....
A model for solar constant secular changes
Schatten, Kenneth H.
1988-01-01
In this paper, contrast models for solar active region and global photospheric features are used to reproduce the observed Active Cavity Radiometer and Earth Radiation Budget secular trends in reasonably good fashion. A prediction for the next decade of solar constant variations is made using the model. Secular trends in the solar constant obtained from the present model support the view that the Maunder Minimum may be related to the Little Ice Age of the 17th century.
A quadri-constant fraction discriminator
International Nuclear Information System (INIS)
Wang Wei; Gu Zhongdao
1992-01-01
A quad Constant Fraction (Amplitude and Rise Time Compensation) Discriminator Circuit is described, which is based on the ECL high-speed dual comparator AD 9687. The CFD (ARCD) is of the constant fraction timing type (the amplitude and rise time compensation timing type) employing a leading edge discriminator to eliminate error triggers caused by noises. A timing walk measurement indicates a timing walk of less than +- 150 ps from -50 mV to -5 V
Renormalization group equations with multiple coupling constants
International Nuclear Information System (INIS)
Ghika, G.; Visinescu, M.
1975-01-01
The main purpose of this paper is to study the renormalization group equations of a renormalizable field theory with multiple coupling constants. A method for the investigation of the asymptotic stability is presented. This method is applied to a gauge theory with Yukawa and self-quartic couplings of scalar mesons in order to find the domains of asymptotic freedom. An asymptotic expansion for the solutions which tend to the origin of the coupling constants is given
RNA structure and scalar coupling constants
Energy Technology Data Exchange (ETDEWEB)
Tinoco, I. Jr.; Cai, Z.; Hines, J.V.; Landry, S.M.; SantaLucia, J. Jr.; Shen, L.X.; Varani, G. [Univ. of California, Berkeley, CA (United States)
1994-12-01
Signs and magnitudes of scalar coupling constants-spin-spin splittings-comprise a very large amount of data that can be used to establish the conformations of RNA molecules. Proton-proton and proton-phosphorus splittings have been used the most, but the availability of {sup 13}C-and {sup 15}N-labeled molecules allow many more coupling constants to be used for determining conformation. We will systematically consider the torsion angles that characterize a nucleotide unit and the coupling constants that depend on the values of these torsion angles. Karplus-type equations have been established relating many three-bond coupling constants to torsion angles. However, one- and two-bond coupling constants can also depend on conformation. Serianni and coworkers measured carbon-proton coupling constants in ribonucleosides and have calculated their values as a function of conformation. The signs of two-bond coupling can be very useful because it is easier to measure a sign than an accurate magnitude.
Massa, Enrico; Nicolaus, Arnold
2011-04-01
the mass-energy-frequency equivalence. Another effort is to monitor the stability of the Pt-Ir prototype: the technologies described in the present issue can be refined and finalized to calculate the mass variation of 1 kg 28Si spheres by monitoring the surface evolution without weighing them on a balance. The last activity is the determination of the mass of a 28Si sphere by electrical measurements using a watt balance and without any reference to the Pt-Ir prototype. In this framework, it will be necessary to demonstrate the mutual consistency and the stability of both the electrical and crystal mise en pratique of a kilogram definition based on a conventional value of the Planck constant. A related issue is to develop suitable procedures and protocols to disseminate the unit of mass from the new realizations. Since the molar Planck constant is well known via the measurement of the Rydberg constant, the accurate measurement of NA also provides an accurate and independent determination of the Planck constant, h. A comparison of the values of the Planck constant obtained via the watt-balance experiment and the NA determination tests quantum mechanics. In fact, the watt-balance value of h depends on solid state physics through the theories of Josephson and quantum Hall effects, whereas the value of h derived from NA depends on atomic physics through the energy level differences in hydrogen and deuterium, whose associated transition frequencies yield information on the Rydberg constant. Grateful thanks are addressed to H-J Pohl for his outstanding project management in Russia, to A K Kaliteevski and his colleagues of the Central Design Bureau of Machine Building and the Institute of Chemistry of High-Purity Substances for their dedication and the punctual delivery of the enriched material, to H Riemann and his staff of the Institut für Kristallzüchtung for the crystal growth, to our directors for their advice and financial support, and to our colleagues for their
Weber, R. J.; Guo, H.; Russell, A. G.; Nenes, A.
2015-12-01
pH is a critical aerosol property that impacts many atmospheric processes, including biogenic secondary organic aerosol formation, gas-particle phase partitioning, and mineral dust or redox metal mobilization. Particle pH has also been linked to adverse health effects. Using a comprehensive data set from the Southern Oxidant and Aerosol Study (SOAS) as the basis for thermodynamic modeling, we have shown that particles are currently highly acidic in the southeastern US, with pH between 0 and 2. Sulfate and ammonium are the main acid-base components that determine particle pH in this region, however they have different sources and their concentrations are changing. Over 15 years of network data show that sulfur dioxide emission reductions have resulted in a roughly 70 percent decrease in sulfate, whereas ammonia emissions, mainly link to agricultural activities, have been largely steady, as have gas phase ammonia concentrations. This has led to the view that particles are becoming more neutralized. However, sensitivity analysis, based on thermodynamic modeling, to changing sulfate concentrations indicates that particles have remained highly acidic over the past decade, despite the large reductions in sulfate. Furthermore, anticipated continued reductions of sulfate and relatively constant ammonia emissions into the future will not significantly change particle pH until sulfate drops to clean continental background levels. The result reshapes our expectation of future particle pH and implies that atmospheric processes and adverse health effects linked to particle acidity will remain unchanged for some time into the future.
Decay constants in soft wall AdS/QCD revisited
Energy Technology Data Exchange (ETDEWEB)
Braga, Nelson R.F., E-mail: braga@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RJ 21941-972 (Brazil); Diles, Saulo, E-mail: smdiles@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RJ 21941-972 (Brazil); Contreras, M.A. Martin, E-mail: ma.martin41@uniandes.edu.co [High Energy Group, Department of Physics, Universidad de los Andes, Carrera 1, No 18A-10, Bloque Ip, ZIP 111711, Bogotá (Colombia)
2016-12-10
Phenomenological AdS/QCD models, like hard wall and soft wall, provide hadronic mass spectra in reasonable consistency with experimental and (or) lattice results. These simple models are inspired in the AdS/CFT correspondence and assume that gauge/gravity duality holds in a scenario where conformal invariance is broken through the introduction of an energy scale. Another important property of hadrons: the decay constant, can also be obtained from these models. However, a consistent formulation of an AdS/QCD model that reproduces the observed behavior of decay constants of vector meson excited states is still lacking. In particular: for radially excited states of heavy vector mesons, the experimental data lead to decay constants that decrease with the radial excitation level. We show here that a modified framework of soft wall AdS/QCD involving an additional dimensionfull parameter, associated with an ultraviolet energy scale, provides decay constants decreasing with radial excitation level. In this version of the soft wall model the two point function of gauge theory operators is calculated at a finite position of the anti-de Sitter space radial coordinate.
Constant-roll (quasi-)linear inflation
Karam, A.; Marzola, L.; Pappas, T.; Racioppi, A.; Tamvakis, K.
2018-05-01
In constant-roll inflation, the scalar field that drives the accelerated expansion of the Universe is rolling down its potential at a constant rate. Within this framework, we highlight the relations between the Hubble slow-roll parameters and the potential ones, studying in detail the case of a single-field Coleman-Weinberg model characterised by a non-minimal coupling of the inflaton to gravity. With respect to the exact constant-roll predictions, we find that assuming an approximate slow-roll behaviour yields a difference of Δ r = 0.001 in the tensor-to-scalar ratio prediction. Such a discrepancy is in principle testable by future satellite missions. As for the scalar spectral index ns, we find that the existing 2-σ bound constrains the value of the non-minimal coupling to ξphi ~ 0.29–0.31 in the model under consideration.
Cosmological constant is a conserved charge
Chernyavsky, Dmitry; Hajian, Kamal
2018-06-01
Cosmological constant can always be considered as the on-shell value of a top form in gravitational theories. The top form is the field strength of a gauge field, and the theory enjoys a gauge symmetry. We show that cosmological constant is the charge of the global part of the gauge symmetry, and is conserved irrespective of the dynamics of the metric and other fields. In addition, we introduce its conjugate chemical potential, and prove the generalized first law of thermodynamics which includes variation of cosmological constant as a conserved charge. We discuss how our new term in the first law is related to the volume–pressure term. In parallel with the seminal Wald entropy, this analysis suggests that pressure can also be considered as a conserved charge.
Fast optimization algorithms and the cosmological constant
Bao, Ning; Bousso, Raphael; Jordan, Stephen; Lackey, Brad
2017-11-01
Denef and Douglas have observed that in certain landscape models the problem of finding small values of the cosmological constant is a large instance of a problem that is hard for the complexity class NP (Nondeterministic Polynomial-time). The number of elementary operations (quantum gates) needed to solve this problem by brute force search exceeds the estimated computational capacity of the observable Universe. Here we describe a way out of this puzzling circumstance: despite being NP-hard, the problem of finding a small cosmological constant can be attacked by more sophisticated algorithms whose performance vastly exceeds brute force search. In fact, in some parameter regimes the average-case complexity is polynomial. We demonstrate this by explicitly finding a cosmological constant of order 10-120 in a randomly generated 1 09-dimensional Arkani-Hamed-Dimopoulos-Kachru landscape.
Conformally invariant braneworld and the cosmological constant
International Nuclear Information System (INIS)
Guendelman, E.I.
2004-01-01
A six-dimensional braneworld scenario based on a model describing the interaction of gravity, gauge fields and 3+1 branes in a conformally invariant way is described. The action of the model is defined using a measure of integration built of degrees of freedom independent of the metric. There is no need to fine tune any bulk cosmological constant or the tension of the two (in the scenario described here) parallel branes to obtain zero cosmological constant, the only solutions are those with zero 4D cosmological constant. The two extra dimensions are compactified in a 'football' fashion and the branes lie on the two opposite poles of the compact 'football-shaped' sphere
Vanishing cosmological constant in elementary particles theory
International Nuclear Information System (INIS)
Pisano, F.; Tonasse, M.D.
1997-01-01
The quest of a vanishing cosmological constant is considered in the simplest anomaly-free chiral gauge extension of the electroweak standard model where the new physics is limited to a well defined additional flavordynamics above the Fermi scale, namely up to a few TeVs by matching the gauge coupling constants at the electroweak scale, and with an extended Higgs structure. In contrast to the electroweak standard model, it is shown how the extended scalar sector of the theory allows a vanishing or a very small cosmological constant. the details of the cancellation mechanism are presented. At accessible energies the theory is indistinguishable from the standard model of elementary particles and it is in agreement with all existing data. (author). 32 refs
Stability constants for silicate adsorbed to ferrihydrite
DEFF Research Database (Denmark)
Hansen, Hans Christian Bruun; Wetche, T.P.; Raulund-Rasmussen, Karsten
1994-01-01
Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption...... experiments in 0.01 m NaNO3 electrolyte (pH 3-6). The surface equilibrium constants were calculated according to the two-layer model by Dzombak & Morel (1990). Near equilibrium between protons/hydroxyls in solution and the ferrihydrite surface was obtained within minutes while equilibration with silicate...
Derivation of the optical constants of anisotropic
Aronson, J. R.; Emslie, A. G.; Smith, E. M.; Strong, P. F.
1985-07-01
This report concerns the development of methods for obtaining the optical constants of anisotropic crystals of the triclinic and monoclinic systems. The principal method used, classical dispersion theory, is adapted to these crystal systems by extending the Lorentz line parameters to include the angles characterizing the individual resonances, and by replacing the dielectric constant by a dielectric tensor. The sample crystals are gypsium, orthoclase and chalcanthite. The derived optical constants are shown to be suitable for modeling the optical properties of particulate media in the infrared spectral region. For those materials where suitable size single crystals are not available, an extension of a previously used method is applied to alabaster, a polycrystalline material of the monoclinic crystal system.
Effects of quantum entropy on bag constant
International Nuclear Information System (INIS)
Miller, D.E.; Tawfik, A.
2012-01-01
The effects of quantum entropy on the bag constant are studied at low temperatures and for small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, Δ and Ω - . In both cases we have found that the bag constant without the quantum entropy almost does not change with temperature and quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant. Furthermore, we construct states densities for quarks using the 'Thomas Fermi model' and take into consideration a thermal potential for the interaction. (author)
Lanz, Leora Halpern; Carmichael, Megan
2015-01-01
The hotel marketing budget, typically amounting to approximately 4-5% of an asset’s total revenue, must remain fluid so that the marketing director can constantly adapt the marketing tools to meet consumer communications methods and demands. Though only a small amount of a hotel’s revenue is traditionally allocated for the marketing budget, the hotel’s success is directly reliant on how effectively that budget is utilized. Thus far in 2015, over 55% percent of hotel bookings are happening onl...
A Bayesian Framework for Remaining Useful Life Estimation
National Aeronautics and Space Administration — The estimation of remaining useful life (RUL) of a faulty component is at the center of system prognostics and health management. It gives operators a potent tool in...
Robotics to Enable Older Adults to Remain Living at Home
Pearce, Alan J.; Adair, Brooke; Miller, Kimberly; Ozanne, Elizabeth; Said, Catherine; Santamaria, Nick; Morris, Meg E.
2012-01-01
Given the rapidly ageing population, interest is growing in robots to enable older people to remain living at home. We conducted a systematic review and critical evaluation of the scientific literature, from 1990 to the present, on the use of robots in aged care. The key research questions were as follows: (1) what is the range of robotic devices available to enable older people to remain mobile, independent, and safe? and, (2) what is the evidence demonstrating that robotic devices are effec...
The Cosmological Constant Problem (1/2)
CERN. Geneva
2015-01-01
I will review the cosmological constant problem as a serious challenge to our notion of naturalness in Physics. Weinberg’s no go theorem is worked through in detail. I review a number of proposals possibly including Linde's universe multiplication, Coleman's wormholes, the fat graviton, and SLED, to name a few. Large distance modifications of gravity are also discussed, with causality considerations pointing towards a global modification as being the most sensible option. The global nature of the cosmological constant problem is also emphasized, and as a result, the sequestering scenario is reviewed in some detail, demonstrating the cancellation of the Standard Model vacuum energy through a global modification of General Relativity.
The Cosmological Constant Problem (2/2)
CERN. Geneva
2015-01-01
I will review the cosmological constant problem as a serious challenge to our notion of naturalness in Physics. Weinberg’s no go theorem is worked through in detail. I review a number of proposals possibly including Linde's universe multiplication, Coleman's wormholes, the fat graviton, and SLED, to name a few. Large distance modifications of gravity are also discussed, with causality considerations pointing towards a global modification as being the most sensible option. The global nature of the cosmological constant problem is also emphasized, and as a result, the sequestering scenario is reviewed in some detail, demonstrating the cancellation of the Standard Model vacuum energy through a global modification of General Relativity.
Atomic weights: no longer constants of nature
Coplen, Tyler B.; Holden, Norman E.
2011-01-01
Many of us were taught that the standard atomic weights we found in the back of our chemistry textbooks or on the Periodic Table of the Chemical Elements hanging on the wall of our chemistry classroom are constants of nature. This was common knowledge for more than a century and a half, but not anymore. The following text explains how advances in chemical instrumentation and isotopic analysis have changed the way we view atomic weights and why they are no longer constants of nature
Planck intermediate results XXIV. Constraints on variations in fundamental constants
DEFF Research Database (Denmark)
Ade, P. A. R.; Aghanim, N.; Arnaud, M.
2015-01-01
cosmological probes. We conclude that independent time variations of the fine structure constant and of the mass of the electron are constrained by Planck to Δ Α/Α = (3.6±3.7) x 10-3 and Δ me/me = (4 ±11) x 10-3 at the 68% confidence level. We also investigate the possibility of a spatial variation of the fine...
International Nuclear Information System (INIS)
Bertolami, Orfeu; Paramos, Jorge
2011-01-01
The purpose of this study is to describe a perfect fluid matter distribution that leads to a constant curvature region, thanks to the effect of a nonminimal coupling. This distribution exhibits a density profile within the range found in the interstellar medium and an adequate matching of the metric components at its boundary. By identifying this constant curvature with the value of the cosmological constant and superimposing the spherical distributions arising from different matter sources throughout the universe, one is able to mimic a large-scale homogeneous cosmological constant solution.
Time constant of logarithmic creep and relaxation
CSIR Research Space (South Africa)
Nabarro, FRN
2001-07-15
Full Text Available length and hardness which vary logarithmically with time. For dimensional reasons, a logarithmic variation must involve a time constant tau characteristic of the process, so that the deformation is proportional to ln(t/tau). Two distinct mechanisms...
A Memorandum Report: Physical Constants of MCE
2016-08-01
the density and surface tension. In effect, this constant is a corrected molar volume = P = MS / = S / where P = Parachor M = molar volume ...3 3. Vapor Pressure of MCE Calculated from the Experimental Data by Method of Least Squares...values were obtained by averaging the determinations for each sample separately, and then averaging those values. **No average was calculated due to
Study on electromagnetic constants of rotational bands
International Nuclear Information System (INIS)
Abdurazakov, A.A.; Adib, Yu.Sh.; Karakhodzhaev, A.K.
1991-01-01
Values of electromagnetic constant S and rotation bands of odd nuclei with Z=64-70 within the mass number change interval A=153-173 are determined. Values of γ-transition mixing parameter with M1+E2 multipolarity are presented. ρ parameter dependence on mass number A is discussed
On the determination of the Hubble constant
International Nuclear Information System (INIS)
Gurzadyan, V.G.; Harutyunyan, V.V.; Kocharyan, A.A.
1990-10-01
The possibility of an alternative determination of the distance scale of the Universe and the Hubble constant based on the numerical analysis of the hierarchical nature of the large scale Universe (galaxies, clusters and superclusters) is proposed. The results of computer experiments performed by means of special numerical algorithms are represented. (author). 9 refs, 7 figs
Dissociative electron attachment to ozone: rate constant
International Nuclear Information System (INIS)
Skalny, J.D.; Cicman, P.; Maerk, T.D.
2002-01-01
The rate constant for dissociative electron attachment to ozone has been derived over the energy range of 0-10 eV by using previously measured cross section data revisited here in regards to discrimination effect occurring during the extraction of ions. The obtained data for both possible channels exhibit the maximum at mean electron energies close to 1 eV. (author)
Running coupling constants of the Luttinger liquid
International Nuclear Information System (INIS)
Boose, D.; Jacquot, J.L.; Polonyi, J.
2005-01-01
We compute the one-loop expressions of two running coupling constants of the Luttinger model. The obtained expressions have a nontrivial momentum dependence with Landau poles. The reason for the discrepancy between our results and those of other studies, which find that the scaling laws are trivial, is explained
Constant force linear permanent magnet actuators
Paulides, J.J.H.; Encica, L.; Meessen, K.J.; Lomonova, E.A.
2009-01-01
In applications, such as vibration isolation, gravity compensation, pick-and-place machines, etc., there is a need for (long-stroke) passive constant force actuators combined with tubular permanent magnet actuators to minimize the power consumption, hence, passively counteract the gravitational
Lifetime of titanium filament at constant current
International Nuclear Information System (INIS)
Chou, T.S.; Lanni, C.
1981-01-01
Titanium Sublimation Pump (TSP) represents the most efficient and the least expensive method to produce Ultra High Vacuum (UHV) in storage rings. In ISABELLE, a proton storage accelerator under construction at Brookhaven National Laboratory, for example, TSP provides a pumping speed for hydrogen of > 2 x 10 6 l/s. Due to the finite life of titanium filaments, new filaments have to be switched in before the end of filament burn out, to ensure smooth operation of the accelerator. Therefore, several operational modes that can be used to activate the TSP were studied. The constant current mode is a convenient way of maintaining constant evaporating rate by increasing the power input while the filament diameter decreases as titanium evaporates. The filaments used in this experiment were standard Varian 916-0024 filaments made of Ti 85%, Mo 15% alloy. During their lifetime at a constant current of 48 amperes, the evaporation rate rose to a maximum at about 10% of their life and then flattened out to a constant value, 0.25 g/hr. The maximum evaporation rate occurs coincidently with the recrystallization of 74% Ti 26% Mo 2 from microstructure crystalline at higher titanium concentration to macrostructure crystalline at lower titanium concentration. As the macrocrystal grows, the slip plane develops at the grain boundary resulting in high resistance at the slip plane which will eventually cause the filament burn out due to local heating
Derivation of the fine-structure constant
International Nuclear Information System (INIS)
Samec, A.
1980-01-01
The fine-structure constant is derived as a dynamical property of quantum electrodynamics. Single-particle solutions of the coupled Maxwell and Dirac equations have a physical charge spectrum. The solutions are used to construct lepton-and quark-like particles. The strong, weak, electromagnetic, and gravitational forces are described as the interactions of complex charges in multiple combinations
International Nuclear Information System (INIS)
Nishino, Seiichi; Sakane, Masao; Ohnami, Masateru
1986-01-01
Experimental study was made on the damage evaluation and estimation of remaining life of SUS 304 stainless steel in creep, low-cycle fatigue and creep-fatigue at 873 K in air. Creep, fatigue and creep-fatigue damage curves were drawn by the method proposed by D.A. Woodford and the relations between these damages and non-destructive parameters, i.e., microvickers hardness and quantities obtained from X-ray diffraction, were discussed. From these tests, the following conclusions were obtained. (1) Constant damage lines in the diagram of remaining lives in creep and fatigue could be drawn by changing load levels during the tests. Constant damage lines in creep-fatigue were also made by a linear damage rule using both static creep and fatigue damage curves, which agree well with the experimental data in creep-fatigue. (2) Microvickers hardness and half-value breadth in X-ray diffraction are appropriate parameters to evaluate creep damage but are not proper to evaluate fatigue damage. Particle size and microstrain obtained by X-ray profile analysis are good parameters to evaluate both creep and fatigue damages. (author)
Forensic considerations when dealing with incinerated human dental remains.
Reesu, Gowri Vijay; Augustine, Jeyaseelan; Urs, Aadithya B
2015-01-01
Establishing the human dental identification process relies upon sufficient post-mortem data being recovered to allow for a meaningful comparison with ante-mortem records of the deceased person. Teeth are the most indestructible components of the human body and are structurally unique in their composition. They possess the highest resistance to most environmental effects like fire, desiccation, decomposition and prolonged immersion. In most natural as well as man-made disasters, teeth may provide the only means of positive identification of an otherwise unrecognizable body. It is imperative that dental evidence should not be destroyed through erroneous handling until appropriate radiographs, photographs, or impressions can be fabricated. Proper methods of physical stabilization of incinerated human dental remains should be followed. The maintenance of integrity of extremely fragile structures is crucial to the successful confirmation of identity. In such situations, the forensic dentist must stabilise these teeth before the fragile remains are transported to the mortuary to ensure preservation of possibly vital identification evidence. Thus, while dealing with any incinerated dental remains, a systematic approach must be followed through each stage of evaluation of incinerated dental remains to prevent the loss of potential dental evidence. This paper presents a composite review of various studies on incinerated human dental remains and discusses their impact on the process of human identification and suggests a step by step approach. Copyright © 2014 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.
A naive Bayes model for robust remaining useful life prediction of lithium-ion battery
International Nuclear Information System (INIS)
Ng, Selina S.Y.; Xing, Yinjiao; Tsui, Kwok L.
2014-01-01
Highlights: • Robustness of RUL predictions for lithium-ion batteries is analyzed quantitatively. • RUL predictions of the same battery over cycle life are evaluated. • RUL predictions of batteries over different operating conditions are evaluated. • Naive Bayes (NB) is proposed for predictions under constant discharge environments. • Its robustness and accuracy are compared with that of support vector machine (SVM). - Abstract: Online state-of-health (SoH) estimation and remaining useful life (RUL) prediction is a critical problem in battery health management. This paper studies the modeling of battery degradation under different usage conditions and ambient temperatures, which is seldom considered in the literature. Li-ion battery RUL prediction under constant operating conditions at different values of ambient temperature and discharge current are considered. A naive Bayes (NB) model is proposed for RUL prediction of batteries under different operating conditions. It is shown in this analysis that under constant discharge environments, the RUL of Li-ion batteries can be predicted with the NB method, irrespective of the exact values of the operating conditions. The case study shows that the NB generates stable and competitive prediction performance over that of the support vector machine (SVM). This also suggests that, while it is well known that the environmental conditions have big impact on the degradation trend, it is the changes in operating conditions of a Li-ion battery over cycle life that makes the Li-ion battery degradation and RUL prediction even more difficult
Directory of Open Access Journals (Sweden)
Abdeldjallil eNaceri
2015-09-01
Full Text Available In our daily life experience, the angular size of an object correlates with its distance from the observer, provided that the physical size of the object remains constant. In this work, we investigated depth perception in action space (i.e., beyond the arm reach, while keeping the angular size of the target object constant. This was achieved by increasing the physical size of the target object as its distance to the observer increased. To the best of our knowledge, this is the first time that a similar protocol has been tested in action space, for distances to the observer ranging from 1.4 to 2.4m. We replicated the task in virtual and real environments and we found that the performance was significantly different between the two environments. In the real environment, all participants perceived the depth of the target object precisely. Whereas, in virtual reality the responses were significantly less precise, although, still above chance level in 16 of the 20 observers. The difference in the discriminability of the stimuli was likely due to different contributions of the convergence and the accommodation cues in the two environments. The values of Weber fractions estimated in our study were compared to those reported in previous studies in peripersonal and action space.
Development of a remaining lifetime management system for NPPS
International Nuclear Information System (INIS)
Galvan, J.C.; Regano, M.; Hevia Ruperez, F.
1994-01-01
The interest evinced by Spain nuclear power plants in providing a tool to support remaining lifetime management led to UNESA's application to OCIDE in 1992, and the latter's approval, for financing the project to develop a Remaining Lifetime Evaluation System for LWR nuclear power plants. This project is currently being developed under UNESA leadership, and the collaboration of three Spanish engineering companies and a research centre. The paper will describe its objectives, activities, current status and prospects. The project is defined in two phases, the first consisting of the identification and analysis of the main ageing phenomena and their significant parameters and specification of the Remaining Lifetime Evaluation System (RLES), and the second implementation of a pilot application of the RLES to verify its effectiveness. (Author)
Remaining life assessment of a high pressure turbine rotor
International Nuclear Information System (INIS)
Nguyen, Ninh; Little, Alfie
2012-01-01
This paper describes finite element and fracture mechanics based modelling work that provides a useful tool for evaluation of the remaining life of a high pressure (HP) steam turbine rotor that had experienced thermal fatigue cracking. An axis-symmetrical model of a HP rotor was constructed. Steam temperature, pressure and rotor speed data from start ups and shut downs were used for the thermal and stress analysis. Operating history and inspection records were used to benchmark the damage experienced by the rotor. Fracture mechanics crack growth analysis was carried out to evaluate the remaining life of the rotor under themal cyclic loading conditions. The work confirmed that the fracture mechanics approach in conjunction with finite element modelling provides a useful tool for assessing the remaining life of high temperature components in power plants.
Construction of Lines of Constant Density and Constant Refractive Index for Ternary Liquid Mixtures.
Tasic, Aleksandar Z.; Djordjevic, Bojan D.
1983-01-01
Demonstrates construction of density constant and refractive index constant lines in triangular coordinate system on basis of systematic experimental determinations of density and refractive index for both homogeneous (single-phase) ternary liquid mixtures (of known composition) and the corresponding binary compositions. Background information,…
On random age and remaining lifetime for populations of items
DEFF Research Database (Denmark)
Finkelstein, M.; Vaupel, J.
2015-01-01
We consider items that are incepted into operation having already a random (initial) age and define the corresponding remaining lifetime. We show that these lifetimes are identically distributed when the age distribution is equal to the equilibrium distribution of the renewal theory. Then we...... develop the population studies approach to the problem and generalize the setting in terms of stationary and stable populations of items. We obtain new stochastic comparisons for the corresponding population ages and remaining lifetimes that can be useful in applications. Copyright (c) 2014 John Wiley...
Sol-gel-derived mesoporous silica films with low dielectric constants
Energy Technology Data Exchange (ETDEWEB)
Seraji, S.; Wu, Yun; Forbess, M.; Limmer, S.J.; Chou, T.; Cao, Guozhong [Washington Univ., Seattle, WA (United States). Dept. of Materials Science and Engineering
2000-11-16
Mesoporous silica films with low dielectric constants and possibly closed pores have been achieved with a multiple step sol-gel processing technique. Crack-free films with approximately 50% porosity and 0.9 {mu}m thicknesses were obtained, a tape-test revealing good adhesion between films and substrates or metal electrodes. Dielectric constants remained virtually unchanged after aging at room temperature at 56% humidity over 6 days. (orig.)
Monthly Variations in Sea Level at the Island of Zanzibar | Mahongo ...
African Journals Online (AJOL)
Western Indian Ocean Journal of Marine Science ... Air pressure and rainfall remained relatively constant during the 20-year study period, but there were trends in sea level, northeast winds, southeast winds and air temperature. Monthly ... The trend in sea level (9%) appeared to be mainly correlated with northeast winds.
Methodology for Extraction of Remaining Sodium of Used Sodium Containers
International Nuclear Information System (INIS)
Jung, Minhwan; Kim, Jongman; Cho, Youngil; Jeong, Jiyoung
2014-01-01
Sodium used as a coolant in the SFR (Sodium-cooled Fast Reactor) reacts easily with most elements due to its high reactivity. If sodium at high temperature leaks outside of a system boundary and makes contact with oxygen, it starts to burn and toxic aerosols are produced. In addition, it generates flammable hydrogen gas through a reaction with water. Hydrogen gas can be explosive within the range of 4.75 vol%. Therefore, the sodium should be handled carefully in accordance with standard procedures even though there is a small amount of target sodium remainings inside the containers and drums used for experiment. After the experiment, all sodium experimental apparatuses should be dismantled carefully through a series of draining, residual sodium extraction, and cleaning if they are no longer reused. In this work, a system for the extraction of the remaining sodium of used sodium drums has been developed and an operation procedure for the system has been established. In this work, a methodology for the extraction of remaining sodium out of the used sodium container has been developed as one of the sodium facility maintenance works. The sodium extraction system for remaining sodium of the used drums was designed and tested successfully. This work will contribute to an establishment of sodium handling technology for PGSFR. (Prototype Gen-IV Sodium-cooled Fast Reactor)
Predicting the Remaining Useful Life of Rolling Element Bearings
DEFF Research Database (Denmark)
Hooghoudt, Jan Otto; Jantunen, E; Yi, Yang
2018-01-01
Condition monitoring of rolling element bearings is of vital importance in order to keep the industrial wheels running. In wind industry this is especially important due to the challenges in practical maintenance. The paper presents an attempt to improve the capability of prediction of remaining...
The experiences of remaining nurse tutors during the transformation ...
African Journals Online (AJOL)
The transformation of public services and education in South Africa is part of the political and socioeconomic transition to democracy. Changes are occurring in every fi eld, including that of the health services. A qualitative study was undertaken to investigate the experiences of the remaining nurse tutors at a school of ...
Remaining childless : Causes and consequences from a life course perspective
Keizer, R.
2010-01-01
Little is know about childless individuals in the Netherlands, although currently one out of every five Dutch individuals remains childless. Who are they? How did they end up being childless? How and to what extent are their life outcomes influenced by their childlessness? By focusing on individual
Molecular genetic identification of skeletal remains of apartheid ...
African Journals Online (AJOL)
The Truth and Reconciliation Commission made significant progress in examining abuses committed during the apartheid era in South Africa. Despite information revealed by the commission, a large number of individuals remained missing when the commission closed its proceedings. This provided the impetus for the ...
Palmar, Patellar, and Pedal Human Remains from Pavlov
Czech Academy of Sciences Publication Activity Database
Trinkaus, E.; Wojtal, P.; Wilczyński, J.; Sázelová, Sandra; Svoboda, Jiří
2017-01-01
Roč. 2017, June (2017), s. 73-101 ISSN 1545-0031 Institutional support: RVO:68081758 Keywords : Gravettian * human remains * isolated bones * anatomically modern humans * Upper Paleolithic Subject RIV: AC - Archeology, Anthropology, Ethnology OBOR OECD: Archaeology http://paleoanthro.org/media/journal/content/PA20170073.pdf
Robotics to Enable Older Adults to Remain Living at Home
Directory of Open Access Journals (Sweden)
Alan J. Pearce
2012-01-01
Full Text Available Given the rapidly ageing population, interest is growing in robots to enable older people to remain living at home. We conducted a systematic review and critical evaluation of the scientific literature, from 1990 to the present, on the use of robots in aged care. The key research questions were as follows: (1 what is the range of robotic devices available to enable older people to remain mobile, independent, and safe? and, (2 what is the evidence demonstrating that robotic devices are effective in enabling independent living in community dwelling older people? Following database searches for relevant literature an initial yield of 161 articles was obtained. Titles and abstracts of articles were then reviewed by 2 independent people to determine suitability for inclusion. Forty-two articles met the criteria for question 1. Of these, 4 articles met the criteria for question 2. Results showed that robotics is currently available to assist older healthy people and people with disabilities to remain independent and to monitor their safety and social connectedness. Most studies were conducted in laboratories and hospital clinics. Currently limited evidence demonstrates that robots can be used to enable people to remain living at home, although this is an emerging smart technology that is rapidly evolving.
Authentic leadership: becoming and remaining an authentic nurse leader.
Murphy, Lin G
2012-11-01
This article explores how chief nurse executives became and remained authentic leaders. Using narrative inquiry, this qualitative study focused on the life stories of participants. Results demonstrate the importance of reframing, reflection in alignment with values, and the courage needed as nurse leaders progress to authenticity.
Robotics to enable older adults to remain living at home.
Pearce, Alan J; Adair, Brooke; Miller, Kimberly; Ozanne, Elizabeth; Said, Catherine; Santamaria, Nick; Morris, Meg E
2012-01-01
Given the rapidly ageing population, interest is growing in robots to enable older people to remain living at home. We conducted a systematic review and critical evaluation of the scientific literature, from 1990 to the present, on the use of robots in aged care. The key research questions were as follows: (1) what is the range of robotic devices available to enable older people to remain mobile, independent, and safe? and, (2) what is the evidence demonstrating that robotic devices are effective in enabling independent living in community dwelling older people? Following database searches for relevant literature an initial yield of 161 articles was obtained. Titles and abstracts of articles were then reviewed by 2 independent people to determine suitability for inclusion. Forty-two articles met the criteria for question 1. Of these, 4 articles met the criteria for question 2. Results showed that robotics is currently available to assist older healthy people and people with disabilities to remain independent and to monitor their safety and social connectedness. Most studies were conducted in laboratories and hospital clinics. Currently limited evidence demonstrates that robots can be used to enable people to remain living at home, although this is an emerging smart technology that is rapidly evolving.
Dinosaur remains from the type Maastrichtian: An update
Weishampel, David B.; Mulder, Eric W A; Dortangs, Rudi W.; Jagt, John W M; Jianu, Coralia Maria; Kuypers, Marcel M M; Peeters, Hans H G; Schulp, Anne S.
1999-01-01
Isolated cranial and post-cranial remains of hadrosaurid dinosaurs have been collected from various outcrops in the type area of the Maastrichtian stage during the last few years. In the present contribution, dentary and maxillary teeth are recorded from the area for the first time. Post-cranial
Fibromyalgia revisited: the challenge to a diagnoses remains
Directory of Open Access Journals (Sweden)
José Eduardo Martinez
2010-12-01
Full Text Available ABSTRACT Fibromyalgia is a clinical syndrome characterized by widespread musculoskeletal pain associated with areas of the body known as tender points which, when pressured gently, cause an exaggerated pain response. The most accepted physiopathological theory is that the pain in fibromyalgia results from an unbalance between the pain transmission stimulus mechanism and the pain inhibition one. The symptoms range from widespread musculoskeletal pain; disruptive sleep patterns; fatigue; short-lived generalized stiffness (generally in the morning; edema sensation and paresthesia. There is a constant association with other functional syndrome such as: depression, anxiety, migraine and irritable bowel syndrome. In 1990 The American College of Rheumatology developed a set of criteria to diagnose fibromyalgia and include it in scientific studies so as to help with the upcoming of a patient´s diagnosis and its follow up.
On Semi-classical Degravitation and the Cosmological Constant Problems
Patil, Subodh P
2010-01-01
In this report, we discuss a candidate mechanism through which one might address the various cosmological constant problems. We first observe that the renormalization of gravitational couplings (induced by integrating out various matter fields) manifests non-local modifications to Einstein's equations as quantum corrected equations of motion. That is, at the loop level, matter sources curvature through a gravitational coupling that is a non-local function of the covariant d'Alembertian. If the functional form of the resulting Newton's `constant' is such that it annihilates very long wavelength sources, but reduces to $1/M^2_{pl}$ ($M_{pl}$ being the 4d Planck mass) for all sources with cosmologically observable wavelengths, we would have a complimentary realization of the degravitation paradigm-- a realization through which its non-linear completion and the corresponding modified Bianchi identities are readily understood. We proceed to consider various theories whose coupling to gravity may a priori induce no...
Improvement to the D0 luminosity monitor constant
International Nuclear Information System (INIS)
Bantley, J.
1996-03-01
The D0 experiment has previously calculated its luminosity using the visible cross section (luminosity monitor constant) for its Level 0 trigger, σ L0 = 48.2 mb, based on the world average pp inelastic cross sections at √s = 1.8 TeV. The error on luminosity had been set at 12%. Recent studies using the MBR and DTUJET Monte Carlo event generators and unbiased D0 data samples have resulted in a more precise determination of the D0 luminosity monitor constant. The result, σ L0 = 46.7 ± 2.5 mb, lowers the central value by 3.1% and reduces the error to 5.4%. 12 refs., 7 figs., 9 tabs
Constant force extensional rheometry of polymer solutions
DEFF Research Database (Denmark)
Szabo, Peter; McKinley, Gareth H.; Clasen, Christian
2012-01-01
We revisit the rapid stretching of a liquid filament under the action of a constant imposed tensile force, a problem which was first considered by Matta and Tytus [J. Non-Newton. Fluid Mech. 35 (1990) 215–229]. A liquid bridge formed from a viscous Newtonian fluid or from a dilute polymer solution...... is first established between two cylindrical disks. The upper disk is held fixed and may be connected to a force transducer while the lower cylinder falls due to gravity. By varying the mass of the falling cylinder and measuring its resulting acceleration, the viscoelastic nature of the elongating fluid...... filament can be probed. In particular, we show that with this constant force pull (CFP) technique it is possible to readily impose very large material strains and strain rates so that the maximum extensibility of the polymer molecules may be quantified. This unique characteristic of the experiment...
Energy Technology Data Exchange (ETDEWEB)
Motohashi, Hayato [Universidad de Valencia-CSIC, Instituto de Fisica Corpuscular (IFIC), Valencia (Spain); Starobinsky, Alexei A. [L.D. Landau Institute for Theoretical Physics, RAS, Moscow (Russian Federation); National Research University Higher School of Economics, Moscow (Russian Federation)
2017-08-15
The previously introduced class of two-parametric phenomenological inflationary models in general relativity in which the slow-roll assumption is replaced by the more general, constant-roll condition is generalized to the case of f(R) gravity. A simple constant-roll condition is defined in the original Jordan frame, and exact expressions for a scalaron potential in the Einstein frame, for a function f(R) (in the parametric form) and for inflationary dynamics are obtained. The region of the model parameters permitted by the latest observational constraints on the scalar spectral index and the tensor-to-scalar ratio of primordial metric perturbations generated during inflation is determined. (orig.)
Benjamin Constant. Libertad, democracia y pluralismo
Directory of Open Access Journals (Sweden)
Claudia Patricia Fonnegra Osorio
2015-12-01
Full Text Available A partir de un enfoque interpretativo, en este artículo se aborda por qué para Benjamin Constant la democracia solo puede darse en donde se presenta una relación necesaria entre la libertad entendida como defensa de los derechos individuales -libertad como independencia o negativa- y la libertad concebida como principio de la participación pública -libertad como autonomía o positiva-. Asimismo, se presenta la importancia que atribuye el autor a las tradiciones que dan vida a la configuración del universo cultural de un pueblo. Se concluye que en la obra de Constant se encuentra una clara defensa del Estado de derecho y del pluralismo, la cual puede iluminar la comprensión de los problemas políticos de la contemporaneidad.
Varying constants, black holes, and quantum gravity
International Nuclear Information System (INIS)
Carlip, S.
2003-01-01
Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models
On determining dose rate constants spectroscopically
International Nuclear Information System (INIS)
Rodriguez, M.; Rogers, D. W. O.
2013-01-01
Purpose: To investigate several aspects of the Chen and Nath spectroscopic method of determining the dose rate constants of 125 I and 103 Pd seeds [Z. Chen and R. Nath, Phys. Med. Biol. 55, 6089–6104 (2010)] including the accuracy of using a line or dual-point source approximation as done in their method, and the accuracy of ignoring the effects of the scattered photons in the spectra. Additionally, the authors investigate the accuracy of the literature's many different spectra for bare, i.e., unencapsulated 125 I and 103 Pd sources. Methods: Spectra generated by 14 125 I and 6 103 Pd seeds were calculated in vacuo at 10 cm from the source in a 2.7 × 2.7 × 0.05 cm 3 voxel using the EGSnrc BrachyDose Monte Carlo code. Calculated spectra used the initial photon spectra recommended by AAPM's TG-43U1 and NCRP (National Council of Radiation Protection and Measurements) Report 58 for the 125 I seeds, or TG-43U1 and NNDC(2000) (National Nuclear Data Center, 2000) for 103 Pd seeds. The emitted spectra were treated as coming from a line or dual-point source in a Monte Carlo simulation to calculate the dose rate constant. The TG-43U1 definition of the dose rate constant was used. These calculations were performed using the full spectrum including scattered photons or using only the main peaks in the spectrum as done experimentally. Statistical uncertainties on the air kerma/history and the dose rate/history were ⩽0.2%. The dose rate constants were also calculated using Monte Carlo simulations of the full seed model. Results: The ratio of the intensity of the 31 keV line relative to that of the main peak in 125 I spectra is, on average, 6.8% higher when calculated with the NCRP Report 58 initial spectrum vs that calculated with TG-43U1 initial spectrum. The 103 Pd spectra exhibit an average 6.2% decrease in the 22.9 keV line relative to the main peak when calculated with the TG-43U1 rather than the NNDC(2000) initial spectrum. The measured values from three different
Some Dynamical Effects of the Cosmological Constant
Axenides, M.; Floratos, E. G.; Perivolaropoulos, L.
Newton's law gets modified in the presence of a cosmological constant by a small repulsive term (antigravity) that is proportional to the distance. Assuming a value of the cosmological constant consistent with the recent SnIa data (Λ~=10-52 m-2), we investigate the significance of this term on various astrophysical scales. We find that on galactic scales or smaller (less than a few tens of kpc), the dynamical effects of the vacuum energy are negligible by several orders of magnitude. On scales of 1 Mpc or larger however we find that the vacuum energy can significantly affect the dynamics. For example we show that the velocity data in the local group of galaxies correspond to galactic masses increased by 35% in the presence of vacuum energy. The effect is even more important on larger low density systems like clusters of galaxies or superclusters.
Daylight calculations using constant luminance curves
Energy Technology Data Exchange (ETDEWEB)
Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda
2005-02-01
This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)
Understanding fine structure constants and three generations
International Nuclear Information System (INIS)
Bennett, D.L.; Nielsen, H.B.
1988-02-01
We put forward a model inspired by random dynamics that relates the smallness of the gauge coupling constants to the number of generations being 'large'. The new element in the present version of our model is the appearance of a free parameter χ that is a measure of the (presumably relatively minor) importance of a term in the plaquette action proportional to the trace in the (1/6, 2, 3) representation of the Standard Model. Calling N gen the number of generations, the sets of allowed (N gen , χN gen )-pairs obtained by imposing the three measured coupling constant values of the Standard Model form three lines. In addition to finding that these lines cross at a single point (as needed for a consistent fit), the intersection occurs with surprising accuracy at the integer N gen = 3 (thereby predicting exactly three generations). It is also encouraging that the parameter χ turns out to be small and positive as expected. (orig.)
Bardeen-Cooper-Schrieffer universal constants generalized
International Nuclear Information System (INIS)
Hazaimeh, A.H.
1992-01-01
Weak- and moderate-coupling BCS superconductivity theory is shown to admit a more general T c formula, wherein T c approaches zero somewhat faster than with the familiar BCS T c -formula. This theory leads to a departure from the universal behavior of the gap-to-T c ratio and is consistent with some recent empirical values for exotic superconductors. This ratio is smaller than the universal BCS value of 3.53 in a way which is consistent with weak electron-boson coupling. Similarly, other universal constants related to specific heat and critical magnetic field are modified. In this dissertation, The author investigates the latter constants for weak-coupling and moderate-coupling and carry out detailed comparisons with experimental data for the cuprates and with the corresponding predictions of strong-coupling theory. This effort is to elucidate the nature of these superconductors with regards to coupling strength within an electron-boson mechanism
Multiphoton amplitude in a constant background field
Ahmad, Aftab; Ahmadiniaz, Naser; Corradini, Olindo; Kim, Sang Pyo; Schubert, Christian
2018-01-01
In this contribution, we present our recent compact master formulas for the multiphoton amplitudes of a scalar propagator in a constant background field using the worldline fomulation of quantum field theory. The constant field has been included nonperturbatively, which is crucial for strong external fields. A possible application is the scattering of photons by electrons in a strong magnetic field, a process that has been a subject of great interest since the discovery of astrophysical objects like radio pulsars, which provide evidence that magnetic fields of the order of 1012G are present in nature. The presence of a strong external field leads to a strong deviation from the classical scattering amplitudes. We explicitly work out the Compton scattering amplitude in a magnetic field, which is a process of potential relevance for astrophysics. Our final result is compact and suitable for numerical integration.
Investigation of the effects of constant darkness and light on blood ...
African Journals Online (AJOL)
This study was designed to investigate the effects of constant darkness and light on changes of serum cholesterol, insulin and glucose levels in healthy male rats. In this study, healthy male rats (n = 30) were divided into 3 groups of tens and kept at various light/dark conditions: Control 12:12 light/dark (LD); constant ...
A small cosmological constant and backreaction of non-finetuned parameters
International Nuclear Information System (INIS)
Krause, Axel
2003-01-01
We include the backreaction on warped geometry induced by non-finetuned parameters in a two domain-wall set-up to obtain an exponentially small Cosmological Constant Λ4. The mechanism to suppress the Cosmological Constant involves one classical fine-tuning as compared to an infinity of finetunings at the quantum level in standard D = 4 field theory. (author)
On the Dielectric Constant for Acetanilide: Experimental Measurements and Effect on Energy Transport
Careri, G.; Compatangelo, E.; Christiansen, P. L.; Halding, J.; Skovgaard, O.
1987-01-01
Experimental measurements of the dielectric constant for crystalline acetanilide powder for temperatures ranging from - 140°C to 20°C and for different hydration levels are presented. A Davydov-soliton computer model predicts dramatic changes in the energy transport and storage for typically increased values of the dielectric constant.
Piezooptical constants of Rochelle salt crystals
V.Yo. Stadnyk; M.O. Romanyuk; V.Yu. Kurlyak; V.F.Vachulovych
2000-01-01
The influence of uniaxial mechanical pressure applied along the principal axes and the corresponding bisectors on the birefringent properties of Rochelle salt (RS) crystals are studied. The temperature (77-300 K) and spectral (300-700 nm) dependencies of the effective and absolute piezooptical constants of the RS crystals are calculated. The intercept of dispersion curves of is revealed in the region of the birefringence sign inversion. This testifies that the anizotropy of the piezooptical ...
Simulated annealing with constant thermodynamic speed
International Nuclear Information System (INIS)
Salamon, P.; Ruppeiner, G.; Liao, L.; Pedersen, J.
1987-01-01
Arguments are presented to the effect that the optimal annealing schedule for simulated annealing proceeds with constant thermodynamic speed, i.e., with dT/dt = -(v T)/(ε-√C), where T is the temperature, ε- is the relaxation time, C ist the heat capacity, t is the time, and v is the thermodynamic speed. Experimental results consistent with this conjecture are presented from simulated annealing on graph partitioning problems. (orig.)
A noteworthy dimensionless constant in gravitation theory
International Nuclear Information System (INIS)
Fayos, F.; Lobo, J.A.; Llanta, E.
1986-01-01
A simple problem of gravitation is studied classically and in the Schwarzchild framework. A relationship is found between the parameters that define the trajectories of two particles (the first in radial motion and the second in a circular orbit) which are initially together and meet again after one revolution of particle 2. Dimensional analysis is the clue to explain the appearance of a dimensionless constant in the Newtonian case. (author)
Electromagnetic corrections to pseudoscalar decay constants
Energy Technology Data Exchange (ETDEWEB)
Glaessle, Benjamin Simon
2017-03-06
First principles Lattice quantum chromodynamics (LQCD) calculations enable the determination of low energy hadronic amplitudes. Precision LQCD calculations with relative errors smaller than approximately 1% require the inclusion of electromagnetic effects. We demonstrate that including (quenched) quantum electrodynamics effects in the LQCD calculation effects the values obtained for pseudoscalar decay constants in the per mille range. The importance of systematic effects, including finite volume effects and the charge dependence of renormalization and improvement coefficients, is highlighted.
Cosmological Constant and the Final Anthropic Hypothesis
Cirkovic, Milan M.; Bostrom, Nick
1999-01-01
The influence of recent detections of a finite vacuum energy ("cosmological constant") on our formulation of anthropic conjectures, particularly the so-called Final Anthropic Principle is investigated. It is shown that non-zero vacuum energy implies the onset of a quasi-exponential expansion of our causally connected domain ("the universe") at some point in the future, a stage similar to the inflationary expansion at the very beginning of time. The transition to this future inflationary phase...
Singlet axial constant from QCD sum rules
International Nuclear Information System (INIS)
Belitskij, A.V.; Teryaev, O.V.
1995-01-01
We analyze the singlet axial form factor of the proton for small momentum transferred in the framework of QCD sum rules using the interpolating nucleon current which explicitly accounts for the gluonic degrees of freedom. As the result we come to the quantitative prediction of the singlet axial constant. It is shown that the bilocal power corrections play the most important role in the analysis. 21 refs., 3 figs
Lattice Paths and the Constant Term
International Nuclear Information System (INIS)
Brak, R; Essam, J; Osborn, J; Owczarek, A L; Rechnitzer, A
2006-01-01
We firstly review the constant term method (CTM), illustrating its combinatorial connections and show how it can be used to solve a certain class of lattice path problems. We show the connection between the CTM, the transfer matrix method (eigenvectors and eigenvalues), partial difference equations, the Bethe Ansatz and orthogonal polynomials. Secondly, we solve a lattice path problem first posed in 1971. The model stated in 1971 was only solved for a special case - we solve the full model
Elastic constants from microscopic strain fluctuations
Sengupta; Nielaba; Rao; Binder
2000-02-01
Fluctuations of the instantaneous local Lagrangian strain epsilon(ij)(r,t), measured with respect to a static "reference" lattice, are used to obtain accurate estimates of the elastic constants of model solids from atomistic computer simulations. The measured strains are systematically coarse-grained by averaging them within subsystems (of size L(b)) of a system (of total size L) in the canonical ensemble. Using a simple finite size scaling theory we predict the behavior of the fluctuations as a function of L(b)/L and extract elastic constants of the system in the thermodynamic limit at nonzero temperature. Our method is simple to implement, efficient, and general enough to be able to handle a wide class of model systems, including those with singular potentials without any essential modification. We illustrate the technique by computing isothermal elastic constants of "hard" and "soft" disk triangular solids in two dimensions from Monte Carlo and molecular dynamics simulations. We compare our results with those from earlier simulations and theory.
Emergent gravity in spaces of constant curvature
Energy Technology Data Exchange (ETDEWEB)
Alvarez, Orlando; Haddad, Matthew [Department of Physics, University of Miami,1320 Campo Sano Ave, Coral Gables, FL 33146 (United States)
2017-03-07
In physical theories where the energy (action) is localized near a submanifold of a constant curvature space, there is a universal expression for the energy (or the action). We derive a multipole expansion for the energy that has a finite number of terms, and depends on intrinsic geometric invariants of the submanifold and extrinsic invariants of the embedding of the submanifold. This is the second of a pair of articles in which we try to develop a theory of emergent gravity arising from the embedding of a submanifold into an ambient space equipped with a quantum field theory. Our theoretical method requires a generalization of a formula due to by Hermann Weyl. While the first paper discussed the framework in Euclidean (Minkowski) space, here we discuss how this framework generalizes to spaces of constant sectional curvature. We focus primarily on anti de Sitter space. We then discuss how such a theory can give rise to a cosmological constant and Planck mass that are within reasonable bounds of the experimental values.
Planck Constant Determination from Power Equivalence
Newell, David B.
2000-04-01
Equating mechanical to electrical power links the kilogram, the meter, and the second to the practical realizations of the ohm and the volt derived from the quantum Hall and the Josephson effects, yielding an SI determination of the Planck constant. The NIST watt balance uses this power equivalence principle, and in 1998 measured the Planck constant with a combined relative standard uncertainty of 8.7 x 10-8, the most accurate determination to date. The next generation of the NIST watt balance is now being assembled. Modification to the experimental facilities have been made to reduce the uncertainty components from vibrations and electromagnetic interference. A vacuum chamber has been installed to reduce the uncertainty components associated with performing the experiment in air. Most of the apparatus is in place and diagnostic testing of the balance should begin this year. Once a combined relative standard uncertainty of one part in 10-8 has been reached, the power equivalence principle can be used to monitor the possible drift in the artifact mass standard, the kilogram, and provide an accurate alternative definition of mass in terms of fundamental constants. *Electricity Division, Electronics and Electrical Engineering Laboratory, Technology Administration, U.S. Department of Commerce. Contribution of the National Institute of Standards and Technology, not subject to copyright in the U.S.
Constant leverage and constant cost of capital : A common knowledge half-truth
Vélez Pareja, Ignacio; Ibragimov, Rauf; Tham , Joseph
2008-01-01
Un enfoque típico para valorar flujos de caja finitos es suponer que el endeudamiento es constante (generalmente como un endeudamiento objetivo o deseado) y que por tanto, el costo del patrimonio, Ke y el costo promedio ponderado de capital CPPC, también son constantes. Para los flujos de caja perpetuos, y con el costo de la deuda, Kd como la tasa de descuento para el ahorro en impuestos o escudo fiscal, Ke y el CPPC aplicado al flujo de caja libre FCL son constantes si el endeudamiento es co...
Structural remains at the early mediaeval fort at Raibania, Orissa
Directory of Open Access Journals (Sweden)
Bratati Sen
2013-11-01
Full Text Available The fortifications of mediaeval India occupy an eminent position in the history of military architecture. The present paper deals with the preliminary study of the structural remains at the early mediaeval fort at Raibania in the district of Balasore in Orissa. The fort was built of stone very loosely kept together. The three-walled fortification interspersed by two consecutive moats, a feature evidenced at Raibania, which is unparallel in the history of ancient and mediaeval forts and fortifications in India. Several other structures like the Jay-Chandi Temple Complex, a huge well, numerous tanks and remains of an ancient bridge add to the uniqueness of the Fort in the entire eastern region.
Mineral remains of early life on Earth? On Mars?
Iberall, Robbins E.; Iberall, A.S.
1991-01-01
The oldest sedimentary rocks on Earth, the 3.8-Ga Isua Iron-Formation in southwestern Greenland, are metamorphosed past the point where organic-walled fossils would remain. Acid residues and thin sections of these rocks reveal ferric microstructures that have filamentous, hollow rod, and spherical shapes not characteristic of crystalline minerals. Instead, they resemble ferric-coated remains of bacteria. Because there are no earlier sedimentary rocks to study on Earth, it may be necessary to expand the search elsewhere in the solar system for clues to any biotic precursors or other types of early life. A study of morphologies of iron oxide minerals collected in the southern highlands during a Mars sample return mission may therefore help to fill in important gaps in the history of Earth's earliest biosphere. -from Authors
USING CONDITION MONITORING TO PREDICT REMAINING LIFE OF ELECTRIC CABLES
International Nuclear Information System (INIS)
LOFARO, R.; SOO, P.; VILLARAN, M.; GROVE, E.
2001-01-01
Electric cables are passive components used extensively throughout nuclear power stations to perform numerous safety and non-safety functions. It is known that the polymers commonly used to insulate the conductors on these cables can degrade with time; the rate of degradation being dependent on the severity of the conditions in which the cables operate. Cables do not receive routine maintenance and, since it can be very costly, they are not replaced on a regular basis. Therefore, to ensure their continued functional performance, it would be beneficial if condition monitoring techniques could be used to estimate the remaining useful life of these components. A great deal of research has been performed on various condition monitoring techniques for use on electric cables. In a research program sponsored by the U.S. Nuclear Regulatory Commission, several promising techniques were evaluated and found to provide trendable information on the condition of low-voltage electric cables. These techniques may be useful for predicting remaining life if well defined limiting values for the aging properties being measured can be determined. However, each technique has advantages and limitations that must be addressed in order to use it effectively, and the necessary limiting values are not always easy to obtain. This paper discusses how condition monitoring measurements can be used to predict the remaining useful life of electric cables. The attributes of an appropriate condition monitoring technique are presented, and the process to be used in estimating the remaining useful life of a cable is discussed along with the difficulties that must be addressed
Study on remain actinides recovery in pyro reprocessing
International Nuclear Information System (INIS)
Suharto, Bambang
1996-01-01
The spent fuel reprocessing by dry process called pyro reprocessing have been studied. Most of U, Pu and MA (minor actinides) from the spent fuel will be recovered and be fed back to the reactor as new fuel. Accumulation of remain actinides will be separated by extraction process with liquid cadmium solvent. The research was conducted by computer simulation to calculate the stage number required. The calculation's results showed on the 20 stages extractor more than 99% actinides can be separated. (author)
US GAAP vs. IFRS – A COMPARISON OF REMAINING DIFFERENCES
Mihelčić, Eva
2008-01-01
In spite of the on-going harmonization process, there are still some differences between US GAAP and IFRS. Currently, companies listed on the New York Stock Exchange, which are reporting according to IFRS, must still prepare the reconciliation to US GAAP, to show the financial statements compliant with US GAAP as well. This article presents an overview of the remaining major differences between US GAAP and IFRS, descriptive as well as table-wise. First, the standards compared are shortly intr...
Structural remains at the early mediaeval fort at Raibania, Orissa
Sen, Bratati
2013-01-01
The fortifications of mediaeval India occupy an eminent position in the history of military architecture. The present paper deals with the preliminary study of the structural remains at the early mediaeval fort at Raibania in the district of Balasore in Orissa. The fort was built of stone very loosely kept together. The three-walled fortification interspersed by two consecutive moats, a feature evidenced at Raibania, w...
Neanderthal infant and adult infracranial remains from Marillac (Charente, France).
Dolores Garralda, María; Maureille, Bruno; Vandermeersch, Bernard
2014-09-01
At the site of Marillac, near the Ligonne River in Marillac-le-Franc (Charente, France), a remarkable stratigraphic sequence has yielded a wealth of archaeological information, palaeoenvironmental data, as well as faunal and human remains. Marillac must have been a sinkhole used by Neanderthal groups as a hunting camp during MIS 4 (TL date 57,600 ± 4,600BP), where Quina Mousterian lithics and fragmented bones of reindeer predominate. This article describes three infracranial skeleton fragments. Two of them are from adults and consist of the incomplete shafts of a right radius (Marillac 24) and a left fibula (Marillac 26). The third fragment is the diaphysis of the right femur of an immature individual (Marillac 25), the size and shape of which resembles those from Teshik-Tash and could be assigned to a child of a similar age. The three fossils have been compared with the remains of other Neanderthals or anatomically Modern Humans (AMH). Furthermore, the comparison of the infantile femora, Marillac 25 and Teshik-Tash, with the remains of several European children from the early Middle Ages clearly demonstrates the robustness and rounded shape of both Neanderthal diaphyses. Evidence of peri-mortem manipulations have been identified on all three bones, with spiral fractures, percussion pits and, in the case of the radius and femur, unquestionable cutmarks made with flint implements, probably during defleshing. Traces of periostosis appear on the fibula fragment and on the immature femoral diaphysis, although their aetiology remains unknown. Copyright © 2014 Wiley Periodicals, Inc.
Calibration of C-14 dates: some remaining uncertainties and limitations
International Nuclear Information System (INIS)
Burleigh, R.
1975-01-01
A brief review is presented of the interpretation of radiocarbon dates in terms of calendar years. An outline is given of the factors that make such correlations necessary and of the work that has so far been done to make them possible. The calibration of the C-14 timescale very largely depends at present on the bristlecone pine chronology, but it is clear that many detailed uncertainties still remain. These are discussed. (U.K.)
Prognostic modelling options for remaining useful life estimation by industry
Sikorska, J. Z.; Hodkiewicz, M.; Ma, L.
2011-07-01
Over recent years a significant amount of research has been undertaken to develop prognostic models that can be used to predict the remaining useful life of engineering assets. Implementations by industry have only had limited success. By design, models are subject to specific assumptions and approximations, some of which are mathematical, while others relate to practical implementation issues such as the amount of data required to validate and verify a proposed model. Therefore, appropriate model selection for successful practical implementation requires not only a mathematical understanding of each model type, but also an appreciation of how a particular business intends to utilise a model and its outputs. This paper discusses business issues that need to be considered when selecting an appropriate modelling approach for trial. It also presents classification tables and process flow diagrams to assist industry and research personnel select appropriate prognostic models for predicting the remaining useful life of engineering assets within their specific business environment. The paper then explores the strengths and weaknesses of the main prognostics model classes to establish what makes them better suited to certain applications than to others and summarises how each have been applied to engineering prognostics. Consequently, this paper should provide a starting point for young researchers first considering options for remaining useful life prediction. The models described in this paper are Knowledge-based (expert and fuzzy), Life expectancy (stochastic and statistical), Artificial Neural Networks, and Physical models.
Remaining useful life estimation based on discriminating shapelet extraction
International Nuclear Information System (INIS)
Malinowski, Simon; Chebel-Morello, Brigitte; Zerhouni, Noureddine
2015-01-01
In the Prognostics and Health Management domain, estimating the remaining useful life (RUL) of critical machinery is a challenging task. Various research topics including data acquisition, fusion, diagnostics and prognostics are involved in this domain. This paper presents an approach, based on shapelet extraction, to estimate the RUL of equipment. This approach extracts, in an offline step, discriminative rul-shapelets from an history of run-to-failure data. These rul-shapelets are patterns that are selected for their correlation with the remaining useful life of the equipment. In other words, every selected rul-shapelet conveys its own information about the RUL of the equipment. In an online step, these rul-shapelets are compared to testing units and the ones that match these units are used to estimate their RULs. Therefore, RUL estimation is based on patterns that have been selected for their high correlation with the RUL. This approach is different from classical similarity-based approaches that attempt to match complete testing units (or only late instants of testing units) with training ones to estimate the RUL. The performance of our approach is evaluated on a case study on the remaining useful life estimation of turbofan engines and performance is compared with other similarity-based approaches. - Highlights: • A data-driven RUL estimation technique based on pattern extraction is proposed. • Patterns are extracted for their correlation with the RUL. • The proposed method shows good performance compared to other techniques
Direct dating of Early Upper Palaeolithic human remains from Mladec.
Wild, Eva M; Teschler-Nicola, Maria; Kutschera, Walter; Steier, Peter; Trinkaus, Erik; Wanek, Wolfgang
2005-05-19
The human fossil assemblage from the Mladec Caves in Moravia (Czech Republic) has been considered to derive from a middle or later phase of the Central European Aurignacian period on the basis of archaeological remains (a few stone artefacts and organic items such as bone points, awls, perforated teeth), despite questions of association between the human fossils and the archaeological materials and concerning the chronological implications of the limited archaeological remains. The morphological variability in the human assemblage, the presence of apparently archaic features in some specimens, and the assumed early date of the remains have made this fossil assemblage pivotal in assessments of modern human emergence within Europe. We present here the first successful direct accelerator mass spectrometry radiocarbon dating of five representative human fossils from the site. We selected sample materials from teeth and from one bone for 14C dating. The four tooth samples yielded uncalibrated ages of approximately 31,000 14C years before present, and the bone sample (an ulna) provided an uncertain more-recent age. These data are sufficient to confirm that the Mladec human assemblage is the oldest cranial, dental and postcranial assemblage of early modern humans in Europe and is therefore central to discussions of modern human emergence in the northwestern Old World and the fate of the Neanderthals.
Remaining life diagnosis method and device for nuclear reactor
International Nuclear Information System (INIS)
Yamamoto, Michiyoshi.
1996-01-01
A neutron flux measuring means is inserted from the outside of a reactor pressure vessel during reactor operation to forecast neutron-degradation of materials of incore structural components in the vicinity of portions to be measured based on the measured values, and the remaining life of the reactor is diagnosed by the forecast degraded state. In this case, the neutron fluxes to be measured are desirably fast and/or medium neutron fluxes. As the positions where the measuring means is to be inserted, for example, the vicinity of the structural components at the periphery of the fuel assembly is selected. Aging degradation characteristics of the structural components are determined by using the aging degradation data for the structural materials. The remaining life is analyzed based on obtained aging degradation characteristics and stress evaluation data of the incore structural components at portions to be measured. Neutron irradiation amount of structural components at predetermined positions can be recognized accurately, and appropriate countermeasures can be taken depending on the forecast remaining life thereby enabling to improve the reliability of the reactor. (N.H.)
Postmortem Scavenging of Human Remains by Domestic Cats
Directory of Open Access Journals (Sweden)
Ananya Suntirukpong, M.D.
2017-11-01
Full Text Available Objective: Crime scene investigators, forensic medicine doctors and pathologists, and forensic anthropologists frequently encounter postmortem scavenging of human remains by household pets. Case presentation: The authors present a case report of a partially skeletonized adult male found dead after more than three months in his apartment in Thailand. The body was in an advanced stage of decomposition with nearly complete skeletonization of the head, neck, hands, and feet. The presence of maggots and necrophagous (flesh eating beetles on the body confirmed that insects had consumed much of the soft tissues. Examination of the hand and foot bones revealed canine tooth puncture marks. Evidence of chewing indicated that one or more of the decedent’s three house cats had fed on the body after death. Recognizing and identifying carnivore and rodent activity on the soft flesh and bones of human remains is important in interpreting and reconstructing postmortem damage. Thorough analysis may help explain why skeletal elements are missing, damaged, or out of anatomical position. Conclusion: This report presents a multi-disciplinary approach combining forensic anthropology and forensic medicine in examining and interpreting human remains.
International Nuclear Information System (INIS)
Sawant, R.M.; Ramakumar, K.L.; Sharma, R.S.
2003-01-01
Protonation constants of hydroquinone and stability constants of thorium hydroquinone complexes were determined in 1 M NaClO 4 medium at 25 ± 0.5 degC, by varying concentration of thorium, using pH titration technique. Protonation constants of hydroquinone (β 1H = [HQ]/[H][Q] and β 2H = [H 2 Q]/[H] 2 [Q]) were found to be β 1H = 11.404 ± 0.014 and β 2H = 21.402 ± 0.012. The analysis of titration data of thorium-hydroquinone system appears to indicate the formation of species Th(H 2 Q) 3 (OH) and Th(H 2 O) 4 (OH). Equilibrium constants obtained for these species are -log β 13-I = 48.51 ± 0.67 and -log β 14-1 64.86 ± 1.25 respectively which are not reported in the literature. (author)
Constant load and constant displacement stress corrosion in simulated water reactor environments
International Nuclear Information System (INIS)
Lloyd, G.J.
1987-02-01
The stress corrosion behaviour of selected water reactor constructional materials, as determined by constant load or constant displacement test techniques, is reviewed. Experimental results obtained using a very wide range of conditions have been collected in a form for easy reference. A discussion is given of some apparent trends in these data. The possible reasons for these trends are considered together with a discussion of how the observed discrepancies may be resolved. (author)
CONSTANT LEVERAGE AND CONSTANT COST OF CAPITAL: A COMMON KNOWLEDGE HALF-TRUTH
Directory of Open Access Journals (Sweden)
IGNACIO VÉLEZ-PAREJA
2008-01-01
Full Text Available Un enfoque típico para valorar flujos de caja finitos es suponer que el endeudamiento es constante (generalmente como un endeudamiento objetivo o deseado y que por tanto, el costo del patrimonio, Ke y el costo promedio ponderado de capital CPPC, también son constantes. Para los flujos de caja perpetuos, y con el costo de la deuda, Kd como la tasa de descuento para el ahorro en impuestos o escudo fiscal, Ke y el CPPC aplicado al flujo de caja libre FCL son constantes si el endeudamiento es constante. Sin embargo esto no es verdad para los flujos de caja finitos. En este documento mostramos que para flujos de caja finitos, Ke y por lo tanto el CPPC dependen de la tasa de descuento que se utiliza para valorar el ahorro en impuestos, AI y según lo esperado, Ke y el CPPC no son constantes con Kd como la tasa de descuento para el ahorro en impuestos, aunque el endeudamiento sea constante. Ilustramos esta situación con un ejemplo simple. Analizamos cinco métodos: el flujo de caja descontado, FCD, usando APV, el FCD y la formulación tradicional y general del CPPC, el valor presente del flujo de caja del accionista, FCA más deuda y el flujo de caja de capital, FCC.
Inflation with a smooth constant-roll to constant-roll era transition
Odintsov, S. D.; Oikonomou, V. K.
2017-07-01
In this paper, we study canonical scalar field models, with a varying second slow-roll parameter, that allow transitions between constant-roll eras. In the models with two constant-roll eras, it is possible to avoid fine-tunings in the initial conditions of the scalar field. We mainly focus on the stability of the resulting solutions, and we also investigate if these solutions are attractors of the cosmological system. We shall calculate the resulting scalar potential and, by using a numerical approach, we examine the stability and attractor properties of the solutions. As we show, the first constant-roll era is dynamically unstable towards linear perturbations, and the cosmological system is driven by the attractor solution to the final constant-roll era. As we demonstrate, it is possible to have a nearly scale-invariant power spectrum of primordial curvature perturbations in some cases; however, this is strongly model dependent and depends on the rate of the final constant-roll era. Finally, we present, in brief, the essential features of a model that allows oscillations between constant-roll eras.
Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical
Adam, Ahmad Y.; Yachmenev, Andrey; Yurchenko, Sergei N.; Jensen, Per
2015-12-01
We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant's equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.
Quantum symmetry, the cosmological constant and Planck-scale phenomenology
International Nuclear Information System (INIS)
Amelino-Camelia, Giovanni; Smolin, Lee; Starodubtsev, Artem
2004-01-01
We present a simple algebraic mechanism for the emergence of deformations of Poincare symmetries in the low-energy limit of quantum theories of gravity. The deformations, called κ-Poincare algebras, are parametrized by a dimensional parameter proportional to the Planck mass, and imply modified energy-momentum relations of a type that may be observable in near future experiments. Our analysis assumes that the low energy limit of a quantum theory of gravity must also involve a limit in which the cosmological constant is taken very small with respect to the Planck scale, and makes use of the fact that in some quantum theories of gravity the cosmological constant results in the (anti)de Sitter symmetry algebra being quantum deformed. We show that deformed Poincare symmetries inevitably emerge in the small-cosmological-constant limit of quantum gravity in 2 + 1 dimensions, where geometry does not have local degrees of freedom. In 3 + 1 dimensions we observe that, besides the quantum deformation of the (anti)de Sitter symmetry algebra, one must also take into account that there are local degrees of freedom leading to a renormalization of the generators for energy and momentum of the excitations. At the present level of development of quantum gravity in 3 + 1 dimensions, it is not yet possible to derive this renormalization from first principles, but we establish the conditions needed for the emergence of a deformed low energy limit symmetry algebra also in the case of 3 + 1 dimensions
Quantum mechanical methods for calculation of force constants
International Nuclear Information System (INIS)
Mullally, D.J.
1985-01-01
The focus of this thesis is upon the calculation of force constants; i.e., the second derivatives of the potential energy with respect to nuclear displacements. This information is useful for the calculation of molecular vibrational modes and frequencies. In addition, it may be used for the location and characterization of equilibrium and transition state geometries. The methods presented may also be applied to the calculation of electric polarizabilities and infrared and Raman vibrational intensities. Two approaches to this problem are studied and evaluated: finite difference methods and analytical techniques. The most suitable method depends on the type and level of theory used to calculate the electronic wave function. Double point displacement finite differencing is often required for accurate calculation of the force constant matrix. These calculations require energy and gradient calculations on both sides of the geometry of interest. In order to speed up these calculations, a novel method is presented that uses geometry dependent information about the wavefunction. A detailed derivation for the analytical evaluation of force constants with a complete active space multiconfiguration self consistent field wave function is presented
Yellow Fever Remains a Potential Threat to Public Health.
Vasconcelos, Pedro F C; Monath, Thomas P
2016-08-01
Yellow fever (YF) remains a serious public health threat in endemic countries. The recent re-emergence in Africa, initiating in Angola and spreading to Democratic Republic of Congo and Uganda, with imported cases in China and Kenya is of concern. There is such a shortage of YF vaccine in the world that the World Health Organization has proposed the use of reduced doses (1/5) during emergencies. In this short communication, we discuss these and other problems including the risk of spread of YF to areas free of YF for decades or never before affected by this arbovirus disease.
The Artificial Leaf: Recent Progress and Remaining Challenges
Directory of Open Access Journals (Sweden)
Mark D Symes
2016-12-01
Full Text Available The prospect of a device that uses solar energy to split water into H2 and O2 is highly attractive in terms of producing hydrogen as a carbon-neutral fuel. In this mini review, key research milestones that have been reached in this field over the last two decades will be discussed, with special focus on devices that use earth-abundant materials. Finally, the remaining challenges in the development of such “artificial leaves” will be highlighted.
Leprosy: ancient disease remains a public health problem nowadays.
Noriega, Leandro Fonseca; Chiacchio, Nilton Di; Noriega, Angélica Fonseca; Pereira, Gilmayara Alves Abreu Maciel; Vieira, Marina Lino
2016-01-01
Despite being an ancient disease, leprosy remains a public health problem in several countries -particularly in India, Brazil and Indonesia. The current operational guidelines emphasize the evaluation of disability from the time of diagnosis and stipulate as fundamental principles for disease control: early detection and proper treatment. Continued efforts are needed to establish and improve quality leprosy services. A qualified primary care network that is integrated into specialized service and the development of educational activities are part of the arsenal in the fight against the disease, considered neglected and stigmatizing.
Studies on protozoa in ancient remains - A Review
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Liesbeth Frías
2013-02-01
Full Text Available Paleoparasitological research has made important contributions to the understanding of parasite evolution and ecology. Although parasitic protozoa exhibit a worldwide distribution, recovering these organisms from an archaeological context is still exceptional and relies on the availability and distribution of evidence, the ecology of infectious diseases and adequate detection techniques. Here, we present a review of the findings related to protozoa in ancient remains, with an emphasis on their geographical distribution in the past and the methodologies used for their retrieval. The development of more sensitive detection methods has increased the number of identified parasitic species, promising interesting insights from research in the future.
Encephalitozoon cuniculi in Raw Cow's Milk Remains Infectious After Pasteurization.
Kváč, Martin; Tomanová, Vendula; Samková, Eva; Koubová, Jana; Kotková, Michaela; Hlásková, Lenka; McEvoy, John; Sak, Bohumil
2016-02-01
This study describes the prevalence of Encephalitozoon cuniculi in raw cow's milk and evaluates the effect of different milk pasteurization treatments on E. cuniculi infectivity for severe combined immunodeficient (SCID) mice. Using a nested polymerase chain reaction approach, 1 of 50 milking cows was found to repeatedly shed E. cuniculi in its feces and milk. Under experimental conditions, E. cuniculi spores in milk remained infective for SCID mice following pasteurization treatments at 72 °C for 15 s or 85 °C for 5 s. Based on these findings, pasteurized cow's milk should be considered a potential source of E. cuniculi infection in humans.
"Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean
Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe
2016-04-01
The examination of surface sediment samples collected from 17 sites along the Lomonosov Ridge at water depths ranging from 737 to 3339 meters during Polarstern Expedition PS87 in 2014 (Stein, 2015), indicates a rich biogenic content almost exclusively dominated by calcareous remains. Amongst biogenic remains, microfossils (planktic and benthic foraminifers, pteropods, ostracods, etc.) dominate but millimetric to centrimetric macrofossils occurred frequently at the surface of the sediment. The macrofossil remains consist of a large variety of taxa, including gastropods, bivalvia, polychaete tubes, scaphopods, echinoderm plates and spines, and fish otoliths. Among the Bivalvia, the most abundant taxa are Portlandia arctica, Hyalopecten frigidus, Cuspidaria glacilis, Policordia densicostata, Bathyarca spp., and Yoldiella spp. Whereas a few specimens are well preserved and apparently pristine, most mollusk shells displayed extensive alteration features. Moreover, most shells were covered by millimeter scale tubes of the serpulid polychaete Spirorbis sp. suggesting transport from low intertidal or subtidal zone. Both the ecological affinity and known geographic distribution of identified bivalvia as named above support the hypothesis of transportation rather than local development. In addition to mollusk shells, more than a hundred fish otoliths were recovered in surface sediments. The otoliths mostly belong to the Gadidae family. Most of them are well preserved and without serpulid tubes attached to their surface, suggesting a local/regional origin, unlike the shell remains. Although recovered at the surface, the macrofaunal assemblages of the Lomonosov Ridge do not necessarily represent the "modern" environments as they may result from reworking and because their occurrence at the surface of the sediment may also be due to winnowing of finer particles. Although the shells were not dated, we suspect that their actual ages may range from modern to several thousands of
Theoretical isochrones with decreasing gravitational constant
International Nuclear Information System (INIS)
Vandenberg, D.A.
1976-01-01
Van Flandern has postulated a variation of the gravitational constant at the rate approximately -8 x 10 -11 /yr. This variation, consistent with Hoyle-Narlikar and Dirac cosmologies, has been assumed in the computation of a 5 x 10 9 yr theoretical isochrone. Present results show that, even for this age, theory predicts a cluster turn-off luminosity approximately 0.5 to 1.0 mag fainter than the observed turn-offs of globular clusters. Unsatisfactory agreement between theoretical and observed luminosity functions is also indicated. (author)
Quantum black holes and Planck's constant
International Nuclear Information System (INIS)
Ross, D.K.
1987-01-01
It is shown that the Planck-scale black holes of quantum gravity must obey a consistency condition relating Planck's constant to the integral of the mass of the black holes over time, if the usual path integral formulation of quantum mechanics is to make sense on physical spacetime. It is also shown, using time-dependent perturbation theory in ordinary quantum mechanics, that a massless particle will not propagate on physical spacetime with the black holes present unless the same condition is met. (author)
Constant displacement rate testing at elevated temperatures
International Nuclear Information System (INIS)
Pepe, J.J.; Gonyea, D.C.
1989-01-01
A short time test has been developed which is capable of determining the long time notch sensitivity tendencies of CrMoV rotor forging materials. This test is based on Constant Displacement Rate (CDR) testing of a specific notch bar specimen at 1200 0 F at 2 mils/in/hour displacement rate. These data were correlated to conventional smooth and notch bar rupture behavior for a series of CrMoV materials with varying long time ductility tendencies. The purpose of this paper is to describe the details of this new test procedure and some of the relevant mechanics of material information generated during its development
Radiation balances and the solar constant
Crommelynck, D.
1981-01-01
The radiometric concepts are defined in order to consider various types of radiation balances and relate them to the diabetic form of the energy balance. Variability in space and time of the components of the radiation field are presented. A specific concept for sweeping which is tailored to the requirements is proposed. Finally, after establishing the truncated character of the present knowledge of the radiation balance. The results of the last observations of the solar constant are given. Ground and satellite measurement techniques are discussed.
O(4) texture with a cosmological constant
International Nuclear Information System (INIS)
Cho, Inyong
2002-01-01
We investigate O(4) textures in a background with a positive cosmological constant. We find static solutions which comove with the expanding background. There exists a solution in which the scalar field is regular at the horizon. This solution has a noninteger winding number smaller than 1. There also exist solutions in which scalar-field derivatives are singular at the horizon. Such solutions can complete one winding within the horizon. If the winding number is larger than some critical value, static solutions including the regular one are unstable under perturbations
Can the cosmological constant undergo abrupt changes?
Cabo-Montes de Oca, Alejandro; Rosabal, A; Cabo, Alejandro; Garcia-Chung, Alejandro; Rosabal, Alejandro
2005-01-01
The existence of a simple spherically symmetric and static solution of the Einstein equations in the presence of a cosmological constant vanishing outside a definite value of the radial distance is investigated. A particular succession of field configurations, which are solutions of the Einstein equations in the presence of the considered cosmological term and auxiliary external sources, is constructed. Then, it is shown that the associated succession of external sources tend to zero in the sense of the generalized functions. The type of weak solution that is found becomes the deSitter homogeneous space-time for the interior region, and the Schwartzschild space in the outside zone.
The Boltzmann constant from a snifter
International Nuclear Information System (INIS)
Tyukodi, B; Sárközi, Zs; Néda, Z; Tunyagi, A; Györke, E
2012-01-01
Evaporation of a small glass of ethylic alcohol is studied both experimentally and through an elementary thermal physics approach. For a cylindrical beaker and no air flow in the room, a simple quadratic relation is found between the evaporation time and the mass of evaporated liquid. This problem and the obtained results offer excellent possibilities for simple student experiments and for testing basic principles of thermal physics. As an example, we use the obtained results for estimating the value of the Boltzmann constant from evaporation experiments. (paper)
Degravitation, inflation and the cosmological constant as an afterglow
International Nuclear Information System (INIS)
Patil, Subodh P.
2009-01-01
In this report, we adopt the phenomenological approach of taking the degravitation paradigm seriously as a consistent modification of gravity in the IR, and investigate its consequences for various cosmological situations. We motivate degravitation — where Netwon's constant is promoted to a scale dependent filter function — as arising from either a small (resonant) mass for the graviton, or as an effect in semi-classical gravity. After addressing how the Bianchi identities are to be satisfied in such a set up, we turn our attention towards the cosmological consequences of degravitation. By considering the example filter function corresponding to a resonantly massive graviton (with a filter scale larger than the present horizon scale), we show that slow roll inflation, hybrid inflation and old inflation remain quantitatively unchanged. We also find that the degravitation mechanism inherits a memory of past energy densities in the present epoch in such a way that is likely significant for present cosmological evolution. For example, if the universe underwent inflation in the past due to it having tunneled out of some false vacuum, we find that degravitation implies a remnant 'afterglow' cosmological constant, whose scale immediately afterwards is parametrically suppressed by the filter scale (L) in Planck units Λ ∼ l 2 pl /L 2 . We discuss circumstances through which this scenario reasonably yields the presently observed value for Λ ∼ O(10 −120 ). We also find that in a universe still currently trapped in some false vacuum state, resonance graviton models of degravitation only degravitate initially Planck or GUT scale energy densities down to the presently observed value over timescales comparable to the filter scale. We argue that different functional forms for the filter function will yield similar conclusions. In this way, we argue that although the degravitation models we study have the potential to explain why the cosmological constant is not large
Krishan, Kewal; Chatterjee, Preetika M; Kanchan, Tanuj; Kaur, Sandeep; Baryah, Neha; Singh, R K
2016-04-01
Sex estimation is considered as one of the essential parameters in forensic anthropology casework, and requires foremost consideration in the examination of skeletal remains. Forensic anthropologists frequently employ morphologic and metric methods for sex estimation of human remains. These methods are still very imperative in identification process in spite of the advent and accomplishment of molecular techniques. A constant boost in the use of imaging techniques in forensic anthropology research has facilitated to derive as well as revise the available population data. These methods however, are less reliable owing to high variance and indistinct landmark details. The present review discusses the reliability and reproducibility of various analytical approaches; morphological, metric, molecular and radiographic methods in sex estimation of skeletal remains. Numerous studies have shown a higher reliability and reproducibility of measurements taken directly on the bones and hence, such direct methods of sex estimation are considered to be more reliable than the other methods. Geometric morphometric (GM) method and Diagnose Sexuelle Probabiliste (DSP) method are emerging as valid methods and widely used techniques in forensic anthropology in terms of accuracy and reliability. Besides, the newer 3D methods are shown to exhibit specific sexual dimorphism patterns not readily revealed by traditional methods. Development of newer and better methodologies for sex estimation as well as re-evaluation of the existing ones will continue in the endeavour of forensic researchers for more accurate results. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
A code of ethics for evidence-based research with ancient human remains.
Kreissl Lonfat, Bettina M; Kaufmann, Ina Maria; Rühli, Frank
2015-06-01
As clinical research constantly advances and the concept of evolution becomes a strong and influential part of basic medical research, the absence of a discourse that deals with the use of ancient human remains in evidence-based research is becoming unbearable. While topics such as exhibition and excavation of human remains are established ethical fields of discourse, when faced with instrumentalization of ancient human remains for research (i.e., ancient DNA extractions for disease marker analyses) the answers from traditional ethics or even more practical fields of bio-ethics or more specific biomedical ethics are rare to non-existent. The Centre for Evolutionary Medicine at the University of Zurich solved their needs for discursive action through the writing of a self-given code of ethics which was written in dialogue with the researchers at the Institute and was published online in Sept. 2011: http://evolutionäremedizin.ch/coe/. The philosophico-ethical basis for this a code of conduct and ethics and the methods are published in this article. © 2015 Wiley Periodicals, Inc.
Constant-Temperature Calorimetry for In-Core Power Measurement
International Nuclear Information System (INIS)
Radcliff, Thomas D.; Miller, Don W.; Kauffman, Andrew C.
2000-01-01
Reactor thermal limits are based on fuel energy deposition and cladding temperature. This paper presents a two-wire in-core instrument that directly measures fuel energy deposition. The instrument is based on the addition of heat through resistive dissipation of input electrical energy to a small mass of reactor fuel or fuel analogue. A feedback loop controls the input electrical energy needed to maintain the fuel mass at a nearly constant temperature regardless of the nuclear energy deposited in the mass. Energy addition to the fuel and fuel temperature feedback to the controller are provided by a resistive heating element embedded in the fuel mass. As long as the external heat transfer environment remains constant, the input electrical energy is inversely related to the actual nuclear energy deposition. To demonstrate this instrument, we first scaled the sensor and controller parameters and then used the results to guide fabrication of prototype instruments. In-reactor testing was performed to measure the instrument sensitivity, linearity, bandwidth, and long-term drift characteristics of the prototypes. The instrument is shown to be capable of high-sensitivity, linear measurement of fuel energy deposition with sufficient bandwidth for safety-related measurements. It is also clear that a means to compensate the sensor for changes in the external heat transfer environment is required. Means of actively measuring heat losses and performing this compensation are discussed
Anisotropic cosmological constant and the CMB quadrupole anomaly
International Nuclear Information System (INIS)
Rodrigues, Davi C.
2008-01-01
There are evidences that the cosmic microwave background (CMB) large-angle anomalies imply a departure from statistical isotropy and hence from the standard cosmological model. We propose a ΛCDM model extension whose dark energy component preserves its nondynamical character but wields anisotropic vacuum pressure. Exact solutions for the cosmological scale factors are presented, upper bounds for the deformation parameter are evaluated and its value is estimated considering the elliptical universe proposal to solve the quadrupole anomaly. This model can be constructed from a Bianchi I cosmology with a cosmological constant from two different ways: (i) a straightforward anisotropic modification of the vacuum pressure consistently with energy-momentum conservation; (ii) a Poisson structure deformation between canonical momenta such that the dynamics remain invariant under scale factors rescalings
Fossil human remains from Bolomor Cave (Valencia, Spain).
Arsuaga, Juan Luis; Fernández Peris, Josep; Gracia-Téllez, Ana; Quam, Rolf; Carretero, José Miguel; Barciela González, Virginia; Blasco, Ruth; Cuartero, Felipe; Sañudo, Pablo
2012-05-01
Systematic excavations carried out since 1989 at Bolomor Cave have led to the recovery of four Pleistocene human fossil remains, consisting of a fibular fragment, two isolated teeth, and a nearly complete adult parietal bone. All of these specimens date to the late Middle and early Late Pleistocene (MIS 7-5e). The fibular fragment shows thick cortical bone, an archaic feature found in non-modern (i.e. non-Homo sapiens) members of the genus Homo. Among the dental remains, the lack of a midtrigonid crest in the M(1) represents a departure from the morphology reported for the majority of Neandertal specimens, while the large dimensions and pronounced shoveling of the marginal ridges in the C(1) are similar to other European Middle and late Pleistocene fossils. The parietal bone is very thick, with dimensions that generally fall above Neandertal fossils and resemble more closely the Middle Pleistocene Atapuerca (SH) adult specimens. Based on the presence of archaic features, all the fossils from Bolomor are attributed to the Neandertal evolutionary lineage. Copyright © 2012 Elsevier Ltd. All rights reserved.
Determination of Remaining Useful Life of Gas Turbine Blade
Directory of Open Access Journals (Sweden)
Meor Said Mior Azman
2016-01-01
Full Text Available The aim of this research is to determine the remaining useful life of gas turbine blade, using service-exposed turbine blades. This task is performed using Stress Rupture Test (SRT under accelerated test conditions where the applied stresses to the specimen is between 400 MPa to 600 MPa and the test temperature is 850°C. The study will focus on the creep behaviour of the 52000 hours service-exposed blades, complemented with creep-rupture modelling using JMatPro software and microstructure examination using optical microscope. The test specimens, made up of Ni-based superalloy of the first stage turbine blades, are machined based on International Standard (ISO 24. The results from the SRT will be analyzed using these two main equations – Larson-Miller Parameter and Life Fraction Rule. Based on the results of the remaining useful life analysis, the 52000h service-exposed blade has the condition to operate in the range of another 4751 hr to 18362 hr. The microstructure examinations shows traces of carbide precipitation that deteriorate the grain boundaries that occurs during creep process. Creep-rupture life modelling using JMatPro software has shown good agreement with the accelerated creep rupture test with minimal error.
A method for defleshing human remains using household bleach.
Mann, Robert W; Berryman, Hugh E
2012-03-01
Medical examiners and forensic anthropologists are often faced with the difficult task of removing soft tissue from the human skeleton without damaging the bones, teeth and, in some cases, cartilage. While there are a number of acceptable methods that can be used to remove soft tissue including macerating in water, simmering or boiling, soaking in ammonia, removing with scissors, knife, scalpel or stiff brush, and dermestid beetles, each has its drawback in time, safety, or potential to damage bone. This technical report using the chest plate of a stabbing victim presents a safe and effective alternative method for removing soft tissue from human remains, in particular the chest plate, following autopsy, without damaging or separating the ribs, sternum, and costal cartilage. This method can be used to reveal subtle blunt force trauma to bone, slicing and stabbing injuries, and other forms of trauma obscured by overlying soft tissue. Despite the published cautionary notes, when done properly household bleach (3-6% sodium hypochlorite) is a quick, safe, and effective method for examining cartilage and exposing skeletal trauma by removing soft tissue from human skeletal remains. 2011 American Academy of Forensic Sciences. Published 2011. This article is a U.S. Government work and is in the public domain in the U.S.A.
Duplex Alu Screening for Degraded DNA of Skeletal Human Remains
Directory of Open Access Journals (Sweden)
Fabian Haß
2017-10-01
Full Text Available The human-specific Alu elements, belonging to the class of Short INterspersed Elements (SINEs, have been shown to be a powerful tool for population genetic studies. An earlier study in this department showed that it was possible to analyze Alu presence/absence in 3000-year-old skeletal human remains from the Bronze Age Lichtenstein cave in Lower Saxony, Germany. We developed duplex Alu screening PCRs with flanking primers for two Alu elements, each combined with a single internal Alu primer. By adding an internal primer, the approximately 400–500 bp presence signals of Alu elements can be detected within a range of less than 200 bp. Thus, our PCR approach is suited for highly fragmented ancient DNA samples, whereas NGS analyses frequently are unable to handle repetitive elements. With this analysis system, we examined remains of 12 individuals from the Lichtenstein cave with different degrees of DNA degradation. The duplex PCRs showed fully informative amplification results for all of the chosen Alu loci in eight of the 12 samples. Our analysis system showed that Alu presence/absence analysis is possible in samples with different degrees of DNA degradation and it reduces the amount of valuable skeletal material needed by a factor of four, as compared with a singleplex approach.
Pair production by a constant external field in noncommutative QED
International Nuclear Information System (INIS)
Chair, N.; Sheikh-Jabbari, M.M.
2000-09-01
In this paper we study QED on the noncommutative space in the constant electro-magnetic field background. Using the explicit solutions of the noncommutative version of Dirac equation in such background, we show that there are well-defined in and out-going asymptotic states and also there is a causal Green's function. We calculate the pair production rate in this case. We show that at tree level noncommutativity will not change the pair production and the threshold electric field. We also calculate the pair production rate considering the first loop corrections. In this case we show that the threshold electric field is decreased by the noncommutativity effects. (author)
The cosmological constant filter without big bang singularity
International Nuclear Information System (INIS)
Bauer, Florian
2011-01-01
In the recently proposed cosmological constant (CC) filter mechanism based on modified gravity in the Palatini formalism, gravity in the radiation, matter and late-time de Sitter eras is insensitive to energy sources with the equation of state -1. This implies that finite vacuum energy shifts from phase transitions are filtered out too. In this work, we investigate the CC filter model at very early times. We find that the initial big bang singularity is replaced by a cosmic bounce, where the matter energy density and the curvature are finite. In a certain case, this finiteness can be already observed on the algebraic level. (paper)
Advances in constant-velocity Moessbauer instrumentation
International Nuclear Information System (INIS)
Veiga, A.; Martinez, N.; Zelis, P. Mendoza; Pasquevich, G. A.; Sanchez, F. H.
2006-01-01
A prototype of a programmable constant-velocity scaler is presented. This instrument allows the acquisition of partial Moessbauer spectra in selected energy regions using standard drivers and transducers. It can be fully operated by a remote application, thus data acquisition can be automated. The instrument consists of a programmable counter and a constant-velocity reference. The reference waveform generator is amplitude modulated with 13-bit resolution, and is programmable in a wide range of frequencies and waveforms in order to optimize the performance of the transducer. The counter is compatible with most standard SCA, and is configured as a rate-meter that provides counts per selectable time slice at the programmed velocity. As a demonstration of the instrument applications, a partial Moessbauer spectrum of a natural iron foil was taken. Only positive energies were studied in 512 channels, accumulating 20 s per channel. A line width of 0.20 mm/s was achieved, performing with an efficiency of 80%.
Ventricular fibrillation time constant for swine
International Nuclear Information System (INIS)
Wu, Jiun-Yan; Sun, Hongyu; Nimunkar, Amit J; Webster, John G; O'Rourke, Ann; Huebner, Shane; Will, James A
2008-01-01
The strength–duration curve for cardiac excitation can be modeled by a parallel resistor–capacitor circuit that has a time constant. Experiments on six pigs were performed by delivering current from the X26 Taser dart at a distance from the heart to cause ventricular fibrillation (VF). The X26 Taser is an electromuscular incapacitation device (EMD), which generates about 50 kV and delivers a pulse train of about 15–19 pulses s −1 with a pulse duration of about 150 µs and peak current about 2 A. Similarly a continuous 60 Hz alternating current of the amplitude required to cause VF was delivered from the same distance. The average current and duration of the current pulse were estimated in both sets of experiments. The strength–duration equation was solved to yield an average time constant of 2.87 ms ± 1.90 (SD). Results obtained may help in the development of safety standards for future electromuscular incapacitation devices (EMDs) without requiring additional animal tests
Simple liquid models with corrected dielectric constants
Fennell, Christopher J.; Li, Libo; Dill, Ken A.
2012-01-01
Molecular simulations often use explicit-solvent models. Sometimes explicit-solvent models can give inaccurate values for basic liquid properties, such as the density, heat capacity, and permittivity, as well as inaccurate values for molecular transfer free energies. Such errors have motivated the development of more complex solvents, such as polarizable models. We describe an alternative here. We give new fixed-charge models of solvents for molecular simulations – water, carbon tetrachloride, chloroform and dichloromethane. Normally, such solvent models are parameterized to agree with experimental values of the neat liquid density and enthalpy of vaporization. Here, in addition to those properties, our parameters are chosen to give the correct dielectric constant. We find that these new parameterizations also happen to give better values for other properties, such as the self-diffusion coefficient. We believe that parameterizing fixed-charge solvent models to fit experimental dielectric constants may provide better and more efficient ways to treat solvents in computer simulations. PMID:22397577
Holographic dark energy with cosmological constant
Hu, Yazhou; Li, Miao; Li, Nan; Zhang, Zhenhui
2015-08-01
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ωhde are divided into a few domains in which the fate of the universe is quite different. We investigate dynamical behaviors of this model, and especially the future evolution of the universe. We perform fitting analysis on the cosmological parameters in the ΛHDE model by using the recent observational data. We find the model yields χ2min=426.27 when constrained by Planck+SNLS3+BAO+HST, comparable to the results of the HDE model (428.20) and the concordant ΛCDM model (431.35). At 68.3% CL, we obtain -0.07<ΩΛ0<0.68 and correspondingly 0.04<Ωhde0<0.79, implying at present there is considerable degeneracy between the holographic dark energy and cosmological constant components in the ΛHDE model.
Holographic dark energy with cosmological constant
Energy Technology Data Exchange (ETDEWEB)
Hu, Yazhou; Li, Nan; Zhang, Zhenhui [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190 (China); Li, Miao, E-mail: asiahu@itp.ac.cn, E-mail: mli@itp.ac.cn, E-mail: linan@itp.ac.cn, E-mail: zhangzhh@mail.ustc.edu.cn [School of Astronomy and Space Science, Sun Yat-Sen University, Guangzhou 510275 (China)
2015-08-01
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ω{sub hde} are divided into a few domains in which the fate of the universe is quite different. We investigate dynamical behaviors of this model, and especially the future evolution of the universe. We perform fitting analysis on the cosmological parameters in the ΛHDE model by using the recent observational data. We find the model yields χ{sup 2}{sub min}=426.27 when constrained by Planck+SNLS3+BAO+HST, comparable to the results of the HDE model (428.20) and the concordant ΛCDM model (431.35). At 68.3% CL, we obtain −0.07<Ω{sub Λ0}<0.68 and correspondingly 0.04<Ω{sub hde0}<0.79, implying at present there is considerable degeneracy between the holographic dark energy and cosmological constant components in the ΛHDE model.
Holographic dark energy with cosmological constant
International Nuclear Information System (INIS)
Hu, Yazhou; Li, Nan; Zhang, Zhenhui; Li, Miao
2015-01-01
Inspired by the multiverse scenario, we study a heterotic dark energy model in which there are two parts, the first being the cosmological constant and the second being the holographic dark energy, thus this model is named the ΛHDE model. By studying the ΛHDE model theoretically, we find that the parameters d and Ω hde are divided into a few domains in which the fate of the universe is quite different. We investigate dynamical behaviors of this model, and especially the future evolution of the universe. We perform fitting analysis on the cosmological parameters in the ΛHDE model by using the recent observational data. We find the model yields χ 2 min =426.27 when constrained by Planck+SNLS3+BAO+HST, comparable to the results of the HDE model (428.20) and the concordant ΛCDM model (431.35). At 68.3% CL, we obtain −0.07<Ω Λ0 <0.68 and correspondingly 0.04<Ω hde0 <0.79, implying at present there is considerable degeneracy between the holographic dark energy and cosmological constant components in the ΛHDE model
Modified large number theory with constant G
International Nuclear Information System (INIS)
Recami, E.
1983-01-01
The inspiring ''numerology'' uncovered by Dirac, Eddington, Weyl, et al. can be explained and derived when it is slightly modified so to connect the ''gravitational world'' (cosmos) with the ''strong world'' (hadron), rather than with the electromagnetic one. The aim of this note is to show the following. In the present approach to the ''Large Number Theory,'' cosmos and hadrons are considered to be (finite) similar systems, so that the ratio R-bar/r-bar of the cosmos typical length R-bar to the hadron typical length r-bar is constant in time (for instance, if both cosmos and hadrons undergo an expansion/contraction cycle: according to the ''cyclical big-bang'' hypothesis: then R-bar and r-bar can be chosen to be the maximum radii, or the average radii). As a consequence, then gravitational constant G results to be independent of time. The present note is based on work done in collaboration with P.Caldirola, G. D. Maccarrone, and M. Pavsic
Fundamental constants and tests of theory in Rydberg states of hydrogenlike ions.
Jentschura, Ulrich D; Mohr, Peter J; Tan, Joseph N; Wundt, Benedikt J
2008-04-25
A comparison of precision frequency measurements to quantum electrodynamics (QED) predictions for Rydberg states of hydrogenlike ions can yield information on values of fundamental constants and test theory. With the results of a calculation of a key QED contribution reported here, the uncertainty in the theory of the energy levels is reduced to a level where such a comparison can yield an improved value of the Rydberg constant.
Fundamental Constants and Tests of Theory in Rydberg States of Hydrogenlike Ions
International Nuclear Information System (INIS)
Jentschura, Ulrich D.; Mohr, Peter J.; Tan, Joseph N.; Wundt, Benedikt J.
2008-01-01
A comparison of precision frequency measurements to quantum electrodynamics (QED) predictions for Rydberg states of hydrogenlike ions can yield information on values of fundamental constants and test theory. With the results of a calculation of a key QED contribution reported here, the uncertainty in the theory of the energy levels is reduced to a level where such a comparison can yield an improved value of the Rydberg constant
PREFACE: Fundamental Constants in Physics and Metrology
Klose, Volkmar; Kramer, Bernhard
1986-01-01
This volume contains the papers presented at the 70th PTB Seminar which, the second on the subject "Fundamental Constants in Physics and Metrology", was held at the Physikalisch-Technische Bundesanstalt in Braunschweig from October 21 to 22, 1985. About 100 participants from the universities and various research institutes of the Federal Republic of Germany participated in the meeting. Besides a number of review lectures on various broader subjects there was a poster session which contained a variety of topical contributed papers ranging from the theory of the quantum Hall effect to reports on the status of the metrological experiments at the PTB. In addition, the participants were also offered the possibility to visit the PTB laboratories during the course of the seminar. During the preparation of the meeting we noticed that even most of the general subjects which were going to be discussed in the lectures are of great importance in connection with metrological experiments and should be made accessible to the scientific community. This eventually resulted in the idea of the publication of the papers in a regular journal. We are grateful to the editor of Metrologia for providing this opportunity. We have included quite a number of papers from basic physical research. For example, certain aspects of high-energy physics and quantum optics, as well as the many-faceted role of Sommerfeld's fine-structure constant, are covered. We think that questions such as "What are the intrinsic fundamental parameters of nature?" or "What are we doing when we perform an experiment?" can shed new light on the art of metrology, and do, potentially, lead to new ideas. This appears to be especially necessary when we notice the increasing importance of the role of the fundamental constants and macroscopic quantum effects for the definition and the realization of the physical units. In some cases we have reached a point where the limitations of our knowledge of a fundamental constant and
Highly efficient DNA extraction method from skeletal remains
Directory of Open Access Journals (Sweden)
Irena Zupanič Pajnič
2011-03-01
Full Text Available Background: This paper precisely describes the method of DNA extraction developed to acquire high quality DNA from the Second World War skeletal remains. The same method is also used for molecular genetic identification of unknown decomposed bodies in routine forensic casework where only bones and teeth are suitable for DNA typing. We analysed 109 bones and two teeth from WWII mass graves in Slovenia. Methods: We cleaned the bones and teeth, removed surface contaminants and ground the bones into powder, using liquid nitrogen . Prior to isolating the DNA in parallel using the BioRobot EZ1 (Qiagen, the powder was decalcified for three days. The nuclear DNA of the samples were quantified by real-time PCR method. We acquired autosomal genetic profiles and Y-chromosome haplotypes of the bones and teeth with PCR amplification of microsatellites, and mtDNA haplotypes 99. For the purpose of traceability in the event of contamination, we prepared elimination data bases including genetic profiles of the nuclear and mtDNA of all persons who have been in touch with the skeletal remains in any way. Results: We extracted up to 55 ng DNA/g of the teeth, up to 100 ng DNA/g of the femurs, up to 30 ng DNA/g of the tibias and up to 0.5 ng DNA/g of the humerus. The typing of autosomal and YSTR loci was successful in all of the teeth, in 98 % dekalof the femurs, and in 75 % to 81 % of the tibias and humerus. The typing of mtDNA was successful in all of the teeth, and in 96 % to 98 % of the bones. Conclusions: We managed to obtain nuclear DNA for successful STR typing from skeletal remains that were over 60 years old . The method of DNA extraction described here has proved to be highly efficient. We obtained 0.8 to 100 ng DNA/g of teeth or bones and complete genetic profiles of autosomal DNA, Y-STR haplotypes, and mtDNA haplotypes from only 0.5g bone and teeth samples.
TMI in perspective: reactor containment stands up, difficult decisions remain
International Nuclear Information System (INIS)
Corey, G.R.
1979-01-01
Commonwealth Edison Co. is increasing its commitment to nuclear energy after reviewing the performance of the Three Mile Island reactor containment systems. Both the reactor vessel and the secondary containment remained intact and no radiation was reported in the soil or water. The public discussion of energy options which followed the accident will benefit both the public and technical community even if there is a temporary slowdown in nuclear power development. The realities of energy supplies have become evident; i.e., that nuclear and coal are the only available options for the short-term. The discussion should also lead to better personnel training, regulatory reforms, risk-sharing insurance, and international standards. The public hysteria triggered by the accident stemmed partly from the combination of unfortunate incidents and the media coverage, which led to hasty conclusions
Oldest Directly Dated Remains of Sheep in China
Dodson, John; Dodson, Eoin; Banati, Richard; Li, Xiaoqiang; Atahan, Pia; Hu, Songmei; Middleton, Ryan J.; Zhou, Xinying; Nan, Sun
2014-11-01
The origins of domesticated sheep (Ovis sp.) in China remain unknown. Previous workers have speculated that sheep may have been present in China up to 7000 years ago, however many claims are based on associations with archaeological material rather than independent dates on sheep material. Here we present 7 radiocarbon dates on sheep bone from Inner Mongolia, Ningxia and Shaanxi provinces. DNA analysis on one of the bones confirms it is Ovis sp. The oldest ages are about 4700 to 4400 BCE and are thus the oldest objectively dated Ovis material in eastern Asia. The graphitisised bone collagen had δ13C values indicating some millet was represented in the diet. This probably indicates sheep were in a domestic setting where millet was grown. The younger samples had δ13C values indicating that even more millet was in the diet, and this was likely related to changes in foddering practices
On use of radial evanescence remain term in kinematic hardening
International Nuclear Information System (INIS)
Geyer, P.
1995-01-01
This paper presents the interest which lies in non-linear kinematic hardening rule with radial evanescence remain term as proposed for modelling multiaxial ratchetting. From analytical calculations in the case of the tension/torsion test, this ratchetting is compared with that proposed by Armstrong and Frederick. A modification is then proposed for Chaboche's elastoplastic model with two non-linear kinematic variables, by coupling the two types of hardening by means of two scalar parameters. Identification of these two parameters returns to speculate on the directions of strain in order to adjust the ratchetting to experimental observations. Using biaxial ratchetting tests on stainless steel 316 L specimens at ambient temperature, it is shown that satisfactory modelling of multiaxial ratchetting is obtained. (author). 4 refs., 5 figs
Psychotherapy for Borderline Personality Disorder: Progress and Remaining Challenges.
Links, Paul S; Shah, Ravi; Eynan, Rahel
2017-03-01
The main purpose of this review was to critically evaluate the literature on psychotherapies for borderline personality disorder (BPD) published over the past 5 years to identify the progress with remaining challenges and to determine priority areas for future research. A systematic review of the literature over the last 5 years was undertaken. The review yielded 184 relevant abstracts, and after applying inclusion criteria, 16 articles were fully reviewed based on the articles' implications for future research and/or clinical practice. Our review indicated that patients with various severities benefited from psychotherapy; more intensive therapies were not significantly superior to less intensive therapies; enhancing emotion regulation processes and fostering more coherent self-identity were important mechanisms of change; therapies had been extended to patients with BPD and posttraumatic stress disorder; and more research was needed to be directed at functional outcomes.
[Alcohol and work: remaining sober and return to work].
Vittadini, G; Bandirali, M
2007-01-01
One of the most complex alcohol-driven problems is the job loss and the subsequent attempts to return to a professional activity. In order to better understand the issue, an epidemiologic investigation was carried out on a group of 162 alcoholics whilst hospitalised in a specialised clinic. The outcome shows the importance of remaining sober to keep or to be returned to one's own job. Unfortunately, local resources at hand, first of all joining an auto-mutual-help group, re still too little known and thus clearly underemployed. Therefore, an informative action within companies is highly desirable. Those alcoholics suffering from serious illnesses, especially mental ones represent a different issue. For these people a higher involvement of public authorities is desirable in creating protected job openings.
Differential Decomposition Among Pig, Rabbit, and Human Remains.
Dautartas, Angela; Kenyhercz, Michael W; Vidoli, Giovanna M; Meadows Jantz, Lee; Mundorff, Amy; Steadman, Dawnie Wolfe
2018-03-30
While nonhuman animal remains are often utilized in forensic research to develop methods to estimate the postmortem interval, systematic studies that directly validate animals as proxies for human decomposition are lacking. The current project compared decomposition rates among pigs, rabbits, and humans at the University of Tennessee's Anthropology Research Facility across three seasonal trials that spanned nearly 2 years. The Total Body Score (TBS) method was applied to quantify decomposition changes and calculate the postmortem interval (PMI) in accumulated degree days (ADD). Decomposition trajectories were analyzed by comparing the estimated and actual ADD for each seasonal trial and by fuzzy cluster analysis. The cluster analysis demonstrated that the rabbits formed one group while pigs and humans, although more similar to each other than either to rabbits, still showed important differences in decomposition patterns. The decomposition trends show that neither nonhuman model captured the pattern, rate, and variability of human decomposition. © 2018 American Academy of Forensic Sciences.
Reidentification of avian embryonic remains from the cretaceous of mongolia.
Varricchio, David J; Balanoff, Amy M; Norell, Mark A
2015-01-01
Embryonic remains within a small (4.75 by 2.23 cm) egg from the Late Cretaceous, Mongolia are here re-described. High-resolution X-ray computed tomography (HRCT) was used to digitally prepare and describe the enclosed embryonic bones. The egg, IGM (Mongolian Institute for Geology, Ulaanbaatar) 100/2010, with a three-part shell microstructure, was originally assigned to Neoceratopsia implying extensive homoplasy among eggshell characters across Dinosauria. Re-examination finds the forelimb significantly longer than the hindlimbs, proportions suggesting an avian identification. Additional, postcranial apomorphies (strut-like coracoid, cranially located humeral condyles, olecranon fossa, slender radius relative to the ulna, trochanteric crest on the femur, and ulna longer than the humerus) identify the embryo as avian. Presence of a dorsal coracoid fossa and a craniocaudally compressed distal humerus with a strongly angled distal margin support a diagnosis of IGM 100/2010 as an enantiornithine. Re-identification eliminates the implied homoplasy of this tri-laminate eggshell structure, and instead associates enantiornithine birds with eggshell microstructure composed of a mammillary, squamatic, and external zones. Posture of the embryo follows that of other theropods with fore- and hindlimbs folded parallel to the vertebral column and the elbow pointing caudally just dorsal to the knees. The size of the egg and embryo of IGM 100/2010 is similar to the two other Mongolian enantiornithine eggs. Well-ossified skeletons, as in this specimen, characterize all known enantiornithine embryos suggesting precocial hatchlings, comparing closely to late stage embryos of modern precocial birds that are both flight- and run-capable upon hatching. Extensive ossification in enantiornithine embryos may contribute to their relatively abundant representation in the fossil record. Neoceratopsian eggs remain unrecognized in the fossil record.
Reidentification of avian embryonic remains from the cretaceous of mongolia.
Directory of Open Access Journals (Sweden)
David J Varricchio
Full Text Available Embryonic remains within a small (4.75 by 2.23 cm egg from the Late Cretaceous, Mongolia are here re-described. High-resolution X-ray computed tomography (HRCT was used to digitally prepare and describe the enclosed embryonic bones. The egg, IGM (Mongolian Institute for Geology, Ulaanbaatar 100/2010, with a three-part shell microstructure, was originally assigned to Neoceratopsia implying extensive homoplasy among eggshell characters across Dinosauria. Re-examination finds the forelimb significantly longer than the hindlimbs, proportions suggesting an avian identification. Additional, postcranial apomorphies (strut-like coracoid, cranially located humeral condyles, olecranon fossa, slender radius relative to the ulna, trochanteric crest on the femur, and ulna longer than the humerus identify the embryo as avian. Presence of a dorsal coracoid fossa and a craniocaudally compressed distal humerus with a strongly angled distal margin support a diagnosis of IGM 100/2010 as an enantiornithine. Re-identification eliminates the implied homoplasy of this tri-laminate eggshell structure, and instead associates enantiornithine birds with eggshell microstructure composed of a mammillary, squamatic, and external zones. Posture of the embryo follows that of other theropods with fore- and hindlimbs folded parallel to the vertebral column and the elbow pointing caudally just dorsal to the knees. The size of the egg and embryo of IGM 100/2010 is similar to the two other Mongolian enantiornithine eggs. Well-ossified skeletons, as in this specimen, characterize all known enantiornithine embryos suggesting precocial hatchlings, comparing closely to late stage embryos of modern precocial birds that are both flight- and run-capable upon hatching. Extensive ossification in enantiornithine embryos may contribute to their relatively abundant representation in the fossil record. Neoceratopsian eggs remain unrecognized in the fossil record.
Hille, Katharina T; Hetz, Stefan K; Rosendahl, Julia; Braun, Hannah-Sophie; Pieper, Robert; Stumpff, Friederike
2016-01-01
Despite the clinical importance of ruminal acidosis, ruminal buffering continues to be poorly understood. In particular, the constants for the dissociation of H2CO3 and the solubility of CO2 (Henry's constant) have never been stringently determined for ruminal fluid. The pH was measured in parallel directly in the rumen and the reticulum in vivo, and in samples obtained via aspiration from 10 fistulated cows on hay- or concentrate-based diets. The equilibrium constants of the bicarbonate system were measured at 38°C both using the Astrup technique and a newly developed method with titration at 2 levels of partial pressure of CO2 (pCO2; 4.75 and 94.98 kPa), yielding mean values of 0.234 ± 0.005 mmol ∙ L(-1) ∙ kPa(-1) and 6.11 ± 0.02 for Henry's constant and the dissociation constant, respectively (n/n = 31/10). Both reticular pH and the pH of samples measured after removal were more alkalic than those measured in vivo in the rumen (by ΔpH = 0.87 ± 0.04 and 0.26 ± 0.04). The amount of acid or base required to shift the pH of ruminal samples to 6.4 or 5.8 (base excess) differed between the 2 feeding groups. Experimental results are compared with the mathematical predictions of an open 2-buffer Henderson-Hasselbalch equilibrium model. Because pCO2 has pronounced effects on ruminal pH and can decrease rapidly in samples removed from the rumen, introduction of a generally accepted protocol for determining the acid-base status of ruminal fluid with standard levels of pCO2 and measurement of base excess in addition to pH should be considered. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
Data-aware remaining time prediction of business process instances
Polato, M.; Sperduti, A.; Burattin, A.; Leoni, de M.
2014-01-01
Accurate prediction of the completion time of a business process instance would constitute a valuable tool when managing processes under service level agreement constraints. Such prediction, however, is a very challenging task. A wide variety of factors could influence the trend of a process
Salt Marsh Sustainability in New England: Progress and Remaining Challenges
Natural resource managers, conservationists, and scientists described marsh loss and degradation in many New England coastal systems at the 2014 “Effects of Sea Level Rise on Rhode Island’s Salt Marshes” workshop, organized by the Narragansett Bay National Estuarine Research Rese...
Statistical Modelling of the Soil Dielectric Constant
Usowicz, Boguslaw; Marczewski, Wojciech; Bogdan Usowicz, Jerzy; Lipiec, Jerzy
2010-05-01
The dielectric constant of soil is the physical property being very sensitive on water content. It funds several electrical measurement techniques for determining the water content by means of direct (TDR, FDR, and others related to effects of electrical conductance and/or capacitance) and indirect RS (Remote Sensing) methods. The work is devoted to a particular statistical manner of modelling the dielectric constant as the property accounting a wide range of specific soil composition, porosity, and mass density, within the unsaturated water content. Usually, similar models are determined for few particular soil types, and changing the soil type one needs switching the model on another type or to adjust it by parametrization of soil compounds. Therefore, it is difficult comparing and referring results between models. The presented model was developed for a generic representation of soil being a hypothetical mixture of spheres, each representing a soil fraction, in its proper phase state. The model generates a serial-parallel mesh of conductive and capacitive paths, which is analysed for a total conductive or capacitive property. The model was firstly developed to determine the thermal conductivity property, and now it is extended on the dielectric constant by analysing the capacitive mesh. The analysis is provided by statistical means obeying physical laws related to the serial-parallel branching of the representative electrical mesh. Physical relevance of the analysis is established electrically, but the definition of the electrical mesh is controlled statistically by parametrization of compound fractions, by determining the number of representative spheres per unitary volume per fraction, and by determining the number of fractions. That way the model is capable covering properties of nearly all possible soil types, all phase states within recognition of the Lorenz and Knudsen conditions. In effect the model allows on generating a hypothetical representative of
Development code for group constant processing
International Nuclear Information System (INIS)
Su'ud, Z.
1997-01-01
In this paper methods, formalism and algorithm related to group constant processing problem from basic library such as ENDF/B VI will be described. Basically the problems can be grouped as follows; the treatment of resolved resonance using NR approximation, the treatment of unresolved resonance using statistical method, the treatment of low lying resonance using intermediate resonance approximation, the treatment of thermal energy regions, and the treatment group transfer matrices cross sections. it is necessary to treat interference between resonance properly especially in the unresolved region. in this paper the resonance problems are treated based on Breit-wigner method, and doppler function is treated using Pade approximation for calculation efficiency. finally, some samples of calculational result for some nuclei, mainly for comparison between many methods are discussed in this paper
Hawking temperature of constant curvature black holes
International Nuclear Information System (INIS)
Cai Ronggen; Myung, Yun Soo
2011-01-01
The constant curvature (CC) black holes are higher dimensional generalizations of Banados-Teitelboim-Zanelli black holes. It is known that these black holes have the unusual topology of M D-1 xS 1 , where D is the spacetime dimension and M D-1 stands for a conformal Minkowski spacetime in D-1 dimensions. The unusual topology and time-dependence for the exterior of these black holes cause some difficulties to derive their thermodynamic quantities. In this work, by using a globally embedding approach, we obtain the Hawking temperature of the CC black holes. We find that the Hawking temperature takes the same form when using both the static and global coordinates. Also, it is identical to the Gibbons-Hawking temperature of the boundary de Sitter spaces of these CC black holes.
Dielectric Constant Measurements of Solid 4He
Yin, L.; Xia, J. S.; Huan, C.; Sullivan, N. S.; Chan, M. H. W.
2011-03-01
Careful measurements of the dielectric properties of solid 4He have been carried out down to 35 mK, considerably lower than the temperature range of previous studies. The sample was prepared from high purity gas with 3He concentrations of the order of 200 ppb and were formed by the blocked capillary method. The molar volume of the sample was 20.30 cm3. The dielectric constant of the samples was found to be independent of temperature down to 120 mK before showing a continuous increase with decreasing temperature and saturating below 50 mK. The total increase in ɛ is 2 parts in 10-5. The temperature dependence of ɛ mimics the increase in the resonant frequency found in the torsional oscillator studies and also the increase found in the shear modulus measurements.
Parallel computational in nuclear group constant calculation
International Nuclear Information System (INIS)
Su'ud, Zaki; Rustandi, Yaddi K.; Kurniadi, Rizal
2002-01-01
In this paper parallel computational method in nuclear group constant calculation using collision probability method will be discuss. The main focus is on the calculation of collision matrix which need large amount of computational time. The geometry treated here is concentric cylinder. The calculation of collision probability matrix is carried out using semi analytic method using Beckley Naylor Function. To accelerate computation speed some computer parallel used to solve the problem. We used LINUX based parallelization using PVM software with C or fortran language. While in windows based we used socket programming using DELPHI or C builder. The calculation results shows the important of optimal weight for each processor in case there area many type of processor speed
Cosmological constant and general isocurvature initial conditions
International Nuclear Information System (INIS)
Trotta, R.; Riazuelo, A.; Durrer, R.
2003-01-01
We investigate in detail the question of whether a nonvanishing cosmological constant is required by the present-day cosmic microwave background and large scale structure data when general isocurvature initial conditions are taken into account. We also discuss the differences between the usual Bayesian and the frequentist approaches in data analysis. We show that the Cosmic Background Explorer (COBE)-normalized matter power spectrum is dominated by the adiabatic mode and therefore breaks the degeneracy between initial conditions which is present in the cosmic microwave background anisotropies. We find that in a flat universe the Bayesian analysis requires Ω Λ =e0 to more than 3σ, while in the frequentist approach Ω Λ =0 is still within 3σ for a value of h≤0.48. Both conclusions hold regardless of the initial conditions
Constant-parameter capture-recapture models
Brownie, C.; Hines, J.E.; Nichols, J.D.
1986-01-01
Jolly (1982, Biometrics 38, 301-321) presented modifications of the Jolly-Seber model for capture-recapture data, which assume constant survival and/or capture rates. Where appropriate, because of the reduced number of parameters, these models lead to more efficient estimators than the Jolly-Seber model. The tests to compare models given by Jolly do not make complete use of the data, and we present here the appropriate modifications, and also indicate how to carry out goodness-of-fit tests which utilize individual capture history information. We also describe analogous models for the case where young and adult animals are tagged. The availability of computer programs to perform the analysis is noted, and examples are given using output from these programs.
Should the coupling constants be mass dependent in the relativistic mean field models
International Nuclear Information System (INIS)
Levai, P.; Lukacs, B.
1986-05-01
Mass dependent coupling constants are proposed for baryonic resonances in the relativistic mean field model, according to the mass splitting of the SU-6 multiplet. With this choice the negative effective masses are avoided and the system remains nucleon dominated with moderate antidelta abundance. (author)
Universal equations and constants of turbulent motion
International Nuclear Information System (INIS)
Baumert, H Z
2013-01-01
This paper presents a parameter-free theory of shear-generated turbulence at asymptotically high Reynolds numbers in incompressible fluids. It is based on a two-fluids concept. Both components are materially identical and inviscid. The first component is an ensemble of quasi-rigid dipole-vortex tubes (vortex filaments, excitations) as quasi-particles in chaotic motion. The second is a superfluid performing evasive motions between the tubes. The local dipole motions follow Helmholtz' law. The vortex radii scale with the energy-containing length scale. Collisions between quasi-particles lead either to annihilation (likewise rotation, turbulent dissipation) or to scattering (counterrotation, turbulent diffusion). There are analogies with birth and death processes of population dynamics and their master equations and with Landau's two-fluid theory of liquid helium. For free homogeneous decay the theory predicts the turbulent kinetic energy to follow t −1 . With an adiabatic wall condition it predicts the logarithmic law with von Kármán's constant as 1/√(2 π)= 0.399. Likewise rotating couples form localized dissipative patches almost at rest (→ intermittency) wherein under local quasi-steady conditions the spectrum evolves into an ‘Apollonian gear’ as discussed first by Herrmann (1990 Correlation and Connectivity (Dordrecht: Kluwer) pp 108–20). Dissipation happens exclusively at scale zero and at finite scales this system is frictionless and reminds of Prigogine's (1947 Etude Thermodynamique des Phenomenes Irreversibles (Liege: Desoer) p 143) law of minimum (here: zero) entropy production. The theory predicts further the prefactor of the 3D-wavenumber spectrum (a Kolmogorov constant) as 1/3 (4 π) 2/3 =1.802, well within the scatter range of observational, experimental and direct numerical simulation results. (paper)
Universal equations and constants of turbulent motion
Baumert, H. Z.
2013-07-01
This paper presents a parameter-free theory of shear-generated turbulence at asymptotically high Reynolds numbers in incompressible fluids. It is based on a two-fluids concept. Both components are materially identical and inviscid. The first component is an ensemble of quasi-rigid dipole-vortex tubes (vortex filaments, excitations) as quasi-particles in chaotic motion. The second is a superfluid performing evasive motions between the tubes. The local dipole motions follow Helmholtz' law. The vortex radii scale with the energy-containing length scale. Collisions between quasi-particles lead either to annihilation (likewise rotation, turbulent dissipation) or to scattering (counterrotation, turbulent diffusion). There are analogies with birth and death processes of population dynamics and their master equations and with Landau's two-fluid theory of liquid helium. For free homogeneous decay the theory predicts the turbulent kinetic energy to follow t-1. With an adiabatic wall condition it predicts the logarithmic law with von Kármán's constant as 1/\\sqrt {2\\,\\pi }= 0.399 . Likewise rotating couples form localized dissipative patches almost at rest (→ intermittency) wherein under local quasi-steady conditions the spectrum evolves into an ‘Apollonian gear’ as discussed first by Herrmann (1990 Correlation and Connectivity (Dordrecht: Kluwer) pp 108-20). Dissipation happens exclusively at scale zero and at finite scales this system is frictionless and reminds of Prigogine's (1947 Etude Thermodynamique des Phenomenes Irreversibles (Liege: Desoer) p 143) law of minimum (here: zero) entropy production. The theory predicts further the prefactor of the 3D-wavenumber spectrum (a Kolmogorov constant) as \\frac {1}{3}(4\\,\\pi )^{2/3}=1.802 , well within the scatter range of observational, experimental and direct numerical simulation results.
Future Remains: Industrial Heritage at the Hanford Plutonium Works
Freer, Brian
This dissertation argues that U.S. environmental and historic preservation regulations, industrial heritage projects, history, and art only provide partial frameworks for successfully transmitting an informed story into the long range future about nuclear technology and its related environmental legacy. This argument is important because plutonium from nuclear weapons production is toxic to humans in very small amounts, threatens environmental health, has a half-life of 24, 110 years and because the industrial heritage project at Hanford is the first time an entire U.S. Department of Energy weapons production site has been designated a U.S. Historic District. This research is situated within anthropological interest in industrial heritage studies, environmental anthropology, applied visual anthropology, as well as wider discourses on nuclear studies. However, none of these disciplines is really designed or intended to be a completely satisfactory frame of reference for addressing this perplexing challenge of documenting and conveying an informed story about nuclear technology and its related environmental legacy into the long range future. Others have thought about this question and have made important contributions toward a potential solution. Examples here include: future generations movements concerning intergenerational equity as evidenced in scholarship, law, and amongst Native American groups; Nez Perce and Confederated Tribes of the Umatilla Indian Reservation responses to the Hanford End State Vision and Hanford's Canyon Disposition Initiative; as well as the findings of organizational scholars on the advantages realized by organizations that have a long term future perspective. While these ideas inform the main line inquiry of this dissertation, the principal approach put forth by the researcher of how to convey an informed story about nuclear technology and waste into the long range future is implementation of the proposed Future Remains clause, as
Constant Leverage And Constant Cost Of Capital: A Common Knowledge Half-Truth
Directory of Open Access Journals (Sweden)
Ignacio Vélez–Pareja
2008-04-01
In this document we show that for finite cash flows, Ke and hence WACC depend on the discount rate that is used to value the tax shield, TS and as expected, Ke and WACC are not constant with Kd as the discount rate for the tax shield, even if the leverage is constant. We illustrate this situation with a simple example. We analyze five methods: DCF using APV, FCF and traditional and general formulation for WACC, present value of CFE plus debt and Capital Cash Flow, CCF.
New Evidence Links Stellar Remains to Oldest Recorded Supernova
2006-09-01
Recent observations have uncovered evidence that helps to confirm the identification of the remains of one of the earliest stellar explosions recorded by humans. The new study shows that the supernova remnant RCW 86 is much younger than previously thought. As such, the formation of the remnant appears to coincide with a supernova observed by Chinese astronomers in 185 A.D. The study used data from NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory, "There have been previous suggestions that RCW 86 is the remains of the supernova from 185 A.D.," said Jacco Vink of University of Utrecht, the Netherlands, and lead author of the study. "These new X-ray data greatly strengthen the case." When a massive star runs out of fuel, it collapses on itself, creating a supernova that can outshine an entire galaxy. The intense explosion hurls the outer layers of the star into space and produces powerful shock waves. The remains of the star and the material it encounters are heated to millions of degrees and can emit intense X-ray radiation for thousands of years. Animation of a Massive Star Explosion Animation of a Massive Star Explosion In their stellar forensic work, Vink and colleagues studied the debris in RCW 86 to estimate when its progenitor star originally exploded. They calculated how quickly the shocked, or energized, shell is moving in RCW 86, by studying one part of the remnant. They combined this expansion velocity with the size of the remnant and a basic understanding of how supernovas expand to estimate the age of RCW 86. "Our new calculations tell us the remnant is about 2,000 years old," said Aya Bamba, a coauthor from the Institute of Physical and Chemical Research (RIKEN), Japan. "Previously astronomers had estimated an age of 10,000 years." The younger age for RCW 86 may explain an astronomical event observed almost 2000 years ago. In 185 AD, Chinese astronomers (and possibly the Romans) recorded the appearance of a new
Briquettes of plant remains from the greenhouses of Almeria (Spain)
Energy Technology Data Exchange (ETDEWEB)
Callejon-Ferre, A. J.; Lopez-Martinez, J. A.
2009-07-01
Since ancient times, plant biomass has been used as a primary fuel, and today, with the impending depletion of fossil fuels, these vegetal sources constitute a cleaner alternative and furthermore have a multitude of uses. The aim of the present study is to design a method of recycling and reuse of plant wastes from intensive agriculture under plastic, by manufacturing briquettes in an environmentally friendly manner. In Almeria (SE Spain), agriculture generates 769,500 t year{sup -}1 of plant remains from greenhouse-grown horticultural crops, a resource currently used for composting and for producing electricity.With the machinery and procedures of the present study, another potential use has been developed by detoxifying and eliminating the plastic wastes of the original biomass for the fabrication of briquettes for fireplaces. The results were slightly inferior to the commercial briquette from other non-horticultural plant materials (no forestry material), specifically 2512 kJ kg{sup -}1, in the least favourable case. On the contrary, the heating value with respect to the two charcoals was significantly lower, with a difference of 12,142 kJ kg{sup -}1. In conclusion; a procedure, applicable in ecological cultivation without agrochemicals or plastic cords, has been developed and tested to reuse and transform plant materials from intensive cultivation into a stable non-toxic product similar to composite logs, applicable in commercial settings or in residential fireplaces. (Author) 48 refs.
Are the alleged remains of Johann Sebastian Bach authentic?
Zegers, Richard H C; Maas, Mario; Koopman, A Ton G; Maat, George J R
2009-02-16
A skeleton alleged to be that of Johann Sebastian Bach (1685-1750) was exhumed from a graveyard in Leipzig, Germany, in 1894, but its authenticity is not established. In 1895, anatomist Wilhelm His concluded from his examination of the skeleton and reconstruction of the face that it most likely belonged to Bach. In 1949, surgeon Wolfgang Rosenthal noticed exostoses on the skeleton and on x-rays of 11 living organists and proposed a condition, Organistenkrankheit, which he interpreted as evidence that the skeleton was Bach's. However, our critical assessment of the remains analysis raises doubts: the localisation of the grave was dubious, and the methods used by His to reconstruct the face are controversial. Also, our study of the pelvic x-rays of 12 living professional organists failed to find evidence for the existence of Organistenkrankheit. We believe it is unlikely that the skeleton is that of Bach; techniques such as DNA analysis might help resolve the question but, to date, church authorities have not approved their use on the skeleton.
Factors influencing home care nurse intention to remain employed.
Tourangeau, Ann; Patterson, Erin; Rowe, Alissa; Saari, Margaret; Thomson, Heather; MacDonald, Geraldine; Cranley, Lisa; Squires, Mae
2014-11-01
To identify factors affecting Canadian home care nurse intention to remain employed (ITR). In developed nations, healthcare continues to shift into community settings. Although considerable research exists on examining nurse ITR in hospitals, similar research related to nurses employed in home care is limited. In the face of a global nursing shortage, it is important to understand the factors influencing nurse ITR across healthcare sectors. A qualitative exploratory descriptive design was used. Focus groups were conducted with home care nurses. Data were analysed using qualitative content analysis. Six categories of influencing factors were identified by home care nurses as affecting ITR: job characteristics; work structures; relationships/communication; work environment; nurse responses to work; and employment conditions. Findings suggest the following factors influence home care nurse ITR: having autonomy; flexible scheduling; reasonable and varied workloads; supportive work relationships; and receiving adequate pay and benefits. Home care nurses did not identify job satisfaction as a single concept influencing ITR. Home care nursing management should support nurse autonomy, allow flexible scheduling, promote reasonable workloads and create opportunities for team building that strengthen supportive relationships among home care nurses and other health team members. © 2013 John Wiley & Sons Ltd.
Carnivoran remains from the Malapa hominin site, South Africa.
Directory of Open Access Journals (Sweden)
Brian F Kuhn
Full Text Available Recent discoveries at the new hominin-bearing deposits of Malapa, South Africa, have yielded a rich faunal assemblage associated with the newly described hominin taxon Australopithecus sediba. Dating of this deposit using U-Pb and palaeomagnetic methods has provided an age of 1.977 Ma, being one of the most accurately dated, time constrained deposits in the Plio-Pleistocene of southern Africa. To date, 81 carnivoran specimens have been identified at this site including members of the families Canidae, Viverridae, Herpestidae, Hyaenidae and Felidae. Of note is the presence of the extinct taxon Dinofelis cf. D. barlowi that may represent the last appearance date for this species. Extant large carnivores are represented by specimens of leopard (Panthera pardus and brown hyaena (Parahyaena brunnea. Smaller carnivores are also represented, and include the genera Atilax and Genetta, as well as Vulpes cf. V. chama. Malapa may also represent the first appearance date for Felis nigripes (Black-footed cat. The geochronological age of Malapa and the associated hominin taxa and carnivoran remains provide a window of research into mammalian evolution during a relatively unknown period in South Africa and elsewhere. In particular, the fauna represented at Malapa has the potential to elucidate aspects of the evolution of Dinofelis and may help resolve competing hypotheses about faunal exchange between East and Southern Africa during the late Pliocene or early Pleistocene.
DNA Profiling Success Rates from Degraded Skeletal Remains in Guatemala.
Johnston, Emma; Stephenson, Mishel
2016-07-01
No data are available regarding the success of DNA Short Tandem Repeat (STR) profiling from degraded skeletal remains in Guatemala. Therefore, DNA profiling success rates relating to 2595 skeletons from eleven cases at the Forensic Anthropology Foundation of Guatemala (FAFG) are presented. The typical postmortem interval was 30 years. DNA was extracted from bone powder and amplified using Identifiler and Minifler. DNA profiling success rates differed between cases, ranging from 50.8% to 7.0%, the overall success rate for samples was 36.3%. The best DNA profiling success rates were obtained from femur (36.2%) and tooth (33.7%) samples. DNA profiles were significantly better from lower body bones than upper body bones (p = <0.0001). Bone samples from males gave significantly better profiles than samples from females (p = <0.0001). These results are believed to be related to bone density. The findings are important for designing forensic DNA sampling strategies in future victim recovery investigations. © 2016 American Academy of Forensic Sciences.
Using contractors to decommission while remaining as licensee
International Nuclear Information System (INIS)
Rankine, A.
1997-01-01
Over the last few years the role of the United Kingdom Atomic Energy Authority (UKAEA) has changed from one involved in research and development in the field of nuclear power and associated technology, to one of managing the liabilities left over from its previous mission. This period has also seen two significant portions of the organization move to the private sector with sale of the Facilities Services Division to PROCORD and the privatization of AEA Technology. The new UKAEA is therefore a focused liabilities management organization, making the best use of expertise in the private sector in carrying out its mission, but retaining adequate internal resource and expertise to fulful its role and responsibilities as the licensee. UKAEA continues to be committed to giving the highest priority to meeting high standards of safety and environmental protection required of the holder of the Nuclear Site Licence under the Nuclear Installations Act. This paper describes the safety management system within the UKAEA which ensures that UKAEA remains the proper and effective licensee and gives some examples of how this has worked in practice. (author)
Efforts to standardize wildlife toxicity values remain unrealized.
Mayfield, David B; Fairbrother, Anne
2013-01-01
Wildlife toxicity reference values (TRVs) are routinely used during screening level and baseline ecological risk assessments (ERAs). Risk assessment professionals often adopt TRVs from published sources to expedite risk analyses. The US Environmental Protection Agency (USEPA) developed ecological soil screening levels (Eco-SSLs) to provide a source of TRVs that would improve consistency among risk assessments. We conducted a survey and evaluated more than 50 publicly available, large-scale ERAs published in the last decade to evaluate if USEPA's goal of uniformity in the use of wildlife TRVs has been met. In addition, these ERAs were reviewed to understand current practices for wildlife TRV use and development within the risk assessment community. The use of no observed and lowest observed adverse effect levels culled from published compendia was common practice among the majority of ERAs reviewed. We found increasing use over time of TRVs established in the Eco-SSL documents; however, Eco-SSL TRV values were not used in the majority of recent ERAs and there continues to be wide variation in TRVs for commonly studied contaminants (e.g., metals, pesticides, PAHs, and PCBs). Variability in the toxicity values was driven by differences in the key studies selected, dose estimation methods, and use of uncertainty factors. These differences result in TRVs that span multiple orders of magnitude for many of the chemicals examined. This lack of consistency in TRV development leads to highly variable results in ecological risk assessments conducted throughout the United States. Copyright © 2012 SETAC.
Gravity with a cosmological constant from rational curves
Adamo, Tim
2015-11-01
We give a new formula for all tree-level correlators of boundary field insertions in gauged N=8 supergravity in AdS4; this is an analogue of the tree-level S-matrix in anti-de Sitter space. The formula is written in terms of rational maps from the Riemann sphere to twistor space, with no reference to bulk perturbation theory. It is polynomial in the cosmological constant, and equal to the classical scattering amplitudes of supergravity in the flat space limit. The formula is manifestly supersymmetric, independent of gauge choices on twistor space, and equivalent to expressions computed via perturbation theory at 3-point overline{MHV} and n-point MHV. We also show that the formula factorizes and obeys BCFW recursion in twistor space.
Gravity with a cosmological constant from rational curves
International Nuclear Information System (INIS)
Adamo, Tim
2015-01-01
We give a new formula for all tree-level correlators of boundary field insertions in gauged N=8 supergravity in AdS_4; this is an analogue of the tree-level S-matrix in anti-de Sitter space. The formula is written in terms of rational maps from the Riemann sphere to twistor space, with no reference to bulk perturbation theory. It is polynomial in the cosmological constant, and equal to the classical scattering amplitudes of supergravity in the flat space limit. The formula is manifestly supersymmetric, independent of gauge choices on twistor space, and equivalent to expressions computed via perturbation theory at 3-point (MHV)-bar and n-point MHV. We also show that the formula factorizes and obeys BCFW recursion in twistor space.
Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites
Hoover, Richard B.
2005-09-01
rocks, living, cryopreserved and fossilized extremophiles and cyanobacteria. These studies have resulted in the detection of mineralized remains of morphotypes of filamentous cyanobacteria, mats and consortia in many carbonaceous meteorites. These well-preserved and embedded microfossils are consistent with the size, morphology and ultra-microstructure of filamentous trichomic prokaryotes and degraded remains of microfibrils of cyanobacterial sheaths. EDAX elemental studies reveal that the forms in the meteorites often have highly carbonized sheaths in close association with permineralized filaments, trichomes, and microbial cells. The eextensive protocols and methodologies that have been developed to protect the samples from contamination and to distinguish recent contaminants from indigenous microfossils are described recent bio-contaminants. Ratios of critical bioelements (C:O, C:N, C:P, and C:S) reveal dramatic differences between microfossils in Earth rocks and meteorites and in the cells, filaments, trichomes, and hormogonia of recently living cyanobacteria. The results of comparative optical, ESEM and FESEM studies and EDAX elemental analyses of recent cyanobacteria (e.g. Calothrix, Oscillatoria, and Lyngbya) of similar size, morphology and microstructure to microfossils found embedded in the Murchison CM2 and the Orgueil CI1 carbonaceous meteorites are presented
Clarifying some remaining questions in the anomaly puzzle
International Nuclear Information System (INIS)
Huang, Xing; Parker, Leonard
2011-01-01
We discuss several points that may help to clarify some questions that remain about the anomaly puzzle in supersymmetric theories. In particular, we consider a general N=1 supersymmetric Yang-Mills theory. The anomaly puzzle concerns the question of whether there is a consistent way in the quantized theory to put the R-current and the stress tensor in a single supermultiplet called the supercurrent, even though in the classical theory they are in the same supermultiplet. It was proposed that the classically conserved supercurrent bifurcates into two supercurrents having different anomalies in the quantum regime. The most interesting result we obtain is an explicit expression for the lowest component of one of the two supercurrents in 4-dimensional spacetime, namely the supercurrent that has the energy-momentum tensor as one of its components. This expression for the lowest component is an energy-dependent linear combination of two chiral currents, which itself does not correspond to a classically conserved chiral current. The lowest component of the other supercurrent, namely, the R-current, satisfies the Adler-Bardeen theorem. The lowest component of the first supercurrent has an anomaly, which we show is consistent with the anomaly of the trace of the energy-momentum tensor. Therefore, we conclude that there is no consistent way to construct a single supercurrent multiplet that contains the R-current and the stress tensor in the straightforward way originally proposed. We also discuss and try to clarify some technical points in the derivations of the two supercurrents in the literature. These latter points concern the significance of infrared contributions to the NSVZ β-function and the role of the equations of motion in deriving the two supercurrents. (orig.)
Will southern California remain a premium market for natural gas?
International Nuclear Information System (INIS)
John, F.E.
1991-01-01
Average yearly demand for natural gas in southern California totalled just over 3 billion ft 3 /d in 1991 and is projected to increase to just over 3.2 billion ft 3 /d in 2000 and 3.4 billion ft 3 /d in 2010. In the core residential market, demand is being driven by population growth and offset by conservation measures. In the core commercial and industrial market, demand is driven by employment growth and offset by conservation. In the noncore market, natural gas use is expected to fall from 262 million ft 3 /d in 1991 to 223 million ft 3 /d in 2010. Demand for natural gas for cogeneration is expected to either remain stagnant or decrease. The largest potential for market growth in southern California is for utility electric generation. Demand in this sector is expected to increase from 468 million ft 3 /d in 1991 to 1 billion ft 3 in 2010. Air quality concerns furnish a market opportunity for natural gas vehicles, and a substantial increase in natural gas demand might be obtained from even a modest market share of the region's 10 million vehicles. Existing pipeline capacity is sufficient to supply current average year requirements, and the need for new capacity hinges on the issues of satisfying high-year demand, meeting market growth, and accessing more desirable supply regions. Planned capacity additions of 2,150 million ft 3 /d, if completed, will bring substantial excess capacity to southern California in the late 1990s. The competitive advantages of various producing regions will then be greatly influenced by the rate designs used on the pipelines connecting them to the market. 4 tabs
Neutron activation analysis of the prehistoric and ancient bone remains
International Nuclear Information System (INIS)
Vasidov, A.; Osinskaya, N.S.; Khatamov, Sh.; Rakhmanova, T.; Akhmadshaev, A.Sh.
2006-01-01
Full text: In the work results of the instrumental neutron activation analysis (INAA) of prehistoric bone remains of dinosaurs and ancient bones of bear, archantrop found out on the territory of Uzbekistan are presents. A bone of dinosaur from Mongolia, standard a bone of the person and soils taken from a surface and from of the femoral joint of a dinosaur were also subject to INAA. The INAA method determines of contents of about 30 elements in bones and soils in an interval 0.043-3600 mg / kg. Among found elements Ca (46 %), Sc, Cr, Fe (up to 2.2 g/kg), Ni, Zn, Sr (up to 3.6 g/kg), Sb, Ba, Sb and some others are mainly found in bones. The contents of some elements in bones of dinosaurs reach very high values 280-3200 mg / kg, and are mainly lanthanides La, Ce, Nd, Sm, Eu, Tb, Yb and Lu. In our opinion, lanthanides and some other elements, like As, Br, and Mo in bones were formed as a result of fission of uranium and transuranium elements. Because content of uranium in bones of dinosaurs is very high, up to 180 mg / kg, and those of thorium is 20 mg/ kg. However U and Th in soils are 4.8 mg/kg and 3.7 mg / kg, respectively. The content of uranium in bones of the archantrop is 1.53 mg / kg, while U in standard bone of the human is less than 0,016 mg/kg. (author)
The broad spectrum revisited: evidence from plant remains.
Weiss, Ehud; Wetterstrom, Wilma; Nadel, Dani; Bar-Yosef, Ofer
2004-06-29
The beginning of agriculture is one of the most important developments in human history, with enormous consequences that paved the way for settled life and complex society. Much of the research on the origins of agriculture over the last 40 years has been guided by Flannery's [Flannery, K. V. (1969) in The Domestication and Exploitation of Plants and Animals, eds. Ucko, P. J. & Dimbleby, G. W. (Duckworth, London), pp. 73-100] "broad spectrum revolution" (BSR) hypothesis, which posits that the transition to farming in southwest Asia entailed a period during which foragers broadened their resource base to encompass a wide array of foods that were previously ignored in an attempt to overcome food shortages. Although these resources undoubtedly included plants, nearly all BSR hypothesis-inspired research has focused on animals because of a dearth of Upper Paleolithic archaeobotanical assemblages. Now, however, a collection of >90,000 plant remains, recently recovered from the Stone Age site Ohalo II (23,000 B.P.), Israel, offers insights into the plant foods of the late Upper Paleolithic. The staple foods of this assemblage were wild grasses, pushing back the dietary shift to grains some 10,000 years earlier than previously recognized. Besides the cereals (wild wheat and barley), small-grained grasses made up a large component of the assemblage, indicating that the BSR in the Levant was even broader than originally conceived, encompassing what would have been low-ranked plant foods. Over the next 15,000 years small-grained grasses were gradually replaced by the cereals and ultimately disappeared from the Levantine diet.
Some aspects of preparation and testing of group constants group constant system ABBN-90
International Nuclear Information System (INIS)
Nikolaev, M.N.; Tsiboulia, A.M.; Manturov, G.N.
1996-01-01
This paper presents an overview of activities performed to prepare and test the group constants ABBN-90. The ABBN-90 set is designed for application calculations of fast, intermediate and thermal nuclear reactors. The calculations of subgroup parameters are discussed. The processing code system GRUCON is mentioned in comparison to the NJOY code system. Proposals are made for future activities. (author). Figs, tabs
Material aging and degradation detection and remaining life assessment for plant life management
International Nuclear Information System (INIS)
Ramuhalli, P.; Henager, C.H. Jr.; Griffin, J.W.; Meyer, R.M.; Coble, J.B.; Pitman, S.G.; Bond, L.J.
2012-01-01
One of the major factors that may impact long-term operations is structural material degradation. Detecting materials degradation, estimating the remaining useful life (RUL) of the component, and determining approaches to mitigating the degradation are important from the perspective of long-term operations. In this study, multiple nondestructive measurement and monitoring methods were evaluated for their ability to assess the material degradation state. Metrics quantifying the level of damage from these measurements were defined and evaluated for their ability to provide estimates of remaining life of the component. An example of estimating the RUL from nondestructive measurements of material degradation condition is provided. (author)
Influence of remaining fission products in low-decontaminated fuel on reactor core characteristics
International Nuclear Information System (INIS)
Ohki, Shigeo
2002-07-01
Design study of core, fuel and related fuel cycle system with low-decontaminated fuel has been performed in the framework of the feasibility study (F/S) on commercialized fast reactor cycle systems. This report summarizes the influence on core characteristics of remaining fission products (FPs) in low-decontaminated fuel related to the reprocessing systems nominated in F/S phase I. For simple treatment of the remaining FPs in core neutronics calculation the representative nuclide method parameterized by the FP equivalent coefficient and the FP volume fraction was developed, which enabled an efficient evaluation procedure. As a result of the investigation on the sodium cooled fast reactor with MOX fuel designed in fiscal year 1999, it was found that the pyrochemical reprocessing with molten salt (the RIAR method) brought the largest influence. Nevertheless, it was still within the allowable range. Assuming an infinite-times recycling, the alternations in core characteristics were evaluated as follows: increment of burnup reactivity by 0.5%Δk/kk', decrement of breeding ratio by 0.04, increment of sodium void reactivity by 0.1x10 -2 Δk/kk' and decrement of Doppler constant (in absolute value) by 0.7x10 -3 Tdk/dT. (author)
The Right to Remain Silent in Criminal Trial
Directory of Open Access Journals (Sweden)
Gianina Anemona Radu
2013-05-01
Full Text Available A person's right not to incriminate oneself or to remain silent and not contribute to their own incrimination is a basic requirement of due process, although the right not to testify against oneself is not expressly guaranteed. This legal right is intended to protect the accused/ the defendant against the authorities’ abusive coercion. The scope of the right not to incriminate oneself is related to criminal matter under the Convention, and thus susceptible or applicable to criminal proceedings concerning all types of crimes as a guarantee to a fair trial. The European Court of Justice ruled that despite the fact that art. 6 paragraph 2 of the Convention does not expressly mention the right not to incriminate oneself and the right not to contribute to their own incrimination (nemo tenetur are ipsum accusare these are generally recognized international rules that are in consistence with the notion of “fair trial” stipulated in art. 6. By virtue of the right to silence, the person charged with a crime is free to answer the questions or not, as he/she believes it is in his/her interest. Therefore, the right to silence involves not only the right not to testify against oneself, but also the right of the accused/ defendant not to incriminate oneself. Thus, the accused/defendant cannot be compelled to assist in the production of evidence and cannot be sanctioned for failing to provide certain documents or other evidence. Obligation to testify against personal will, under the constraint of a fine or any other form of coercion constitutes an interference with the negative aspect of the right to freedom of expression which must be necessary in a democratic society. It is essential to clarify certain issues as far as this right is concerned. First of all, the statutory provision in question is specific to adversarial systems, which are found mainly in Anglo-Saxon countries and are totally different from that underlying the current Romanian Criminal
Price of shifting the Hubble constant
Evslin, Jarah; Sen, Anjan A.; Ruchika
2018-05-01
An anisotropic measurement of the baryon acoustic oscillation (BAO) feature fixes the product of the Hubble constant and the acoustic scale H0rd. Therefore, regardless of the dark energy dynamics, to accommodate a higher value of H0 one needs a lower rd and so necessarily a modification of early time cosmology. One must either reduce the age of the Universe at the drag epoch or else the speed of sound in the primordial plasma. The first can be achieved, for example, with dark radiation or very early dark energy, automatically preserving the angular size of the acoustic scale in the cosmic microwave background (CMB) with no modifications to post-recombination dark energy. However, it is known that the simplest such modifications fall afoul of CMB constraints at higher multipoles. As an example, we combine anisotropic BAO with geometric measurements from strong lensing time delays from H0LiCOW and megamasers from the Megamaser Cosmology Project to measure rd, with and without the local distance ladder measurement of H0. We find that the best fit value of rd is indeed quite insensitive to the dark energy model and is also hardly affected by the inclusion of the local distance ladder data.
Trinucleon asymptotic normalization constants including Coulomb effects
International Nuclear Information System (INIS)
Friar, J.L.; Gibson, B.F.; Lehman, D.R.; Payne, G.L.
1982-01-01
Exact theoretical expressions for calculating the trinucleon S- and D-wave asymptotic normalization constants, with and without Coulomb effects, are presented. Coordinate-space Faddeev-type equations are used to generate the trinucleon wave functions, and integral relations for the asymptotic norms are derived within this framework. The definition of the asymptotic norms in the presence of the Coulomb interaction is emphasized. Numerical calculations are carried out for the s-wave NN interaction models of Malfliet and Tjon and the tensor force model of Reid. Comparison with previously published results is made. The first estimate of Coulomb effects for the D-wave asymptotic norm is given. All theoretical values are carefully compared with experiment and suggestions are made for improving the experimental situation. We find that Coulomb effects increase the 3 He S-wave asymptotic norm by less than 1% relative to that of 3 H, that Coulomb effects decrease the 3 He D-wave asymptotic norm by approximately 8% relative to that of 3 H, and that the distorted-wave Born approximation D-state parameter, D 2 , is only 1% smaller in magnitude for 3 He than for 3 H due to compensating Coulomb effects
Magnetically modified biocells in constant magnetic field
Energy Technology Data Exchange (ETDEWEB)
Abramov, E.G.; Panina, L.K. [Saint Petersburg State University, St. Petersburg (Russian Federation); Kolikov, V.A., E-mail: kolikov1@yandex.ru [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation); Bogomolova, E.V. [Botanical Institute of the RAS after V.L.Komarov, St. Petersburg (Russian Federation); Snetov, V.N. [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation); Cherepkova, I.A. [Saint Petersburg State Institute of Technology, St. Petersburg (Russian Federation); Kiselev, A.A. [Institute for Electrophysics and Electric Power of the RAS, St. Petersburg (Russian Federation)
2017-02-01
Paper addresses the inverse problem in determining the area, where the external constant magnetic field captures the biological cells modified by the magnetic nanoparticles. Zero velocity isolines, in area where the modified cells are captured by the magnetic field were determined by numerical method for two locations of the magnet. The problem was solved taking into account the gravitational field, magnetic induction, density of medium, concentration and size of cells, and size and magnetization of nanoparticles attached to the cell. Increase in the number of the nanoparticles attached to the cell and decrease in the cell’ size, enlarges the area, where the modified cells are captured and concentrated by the magnet. Solution is confirmed by the visible pattern formation of the modified cells Saccharomyces cerevisiae. - Highlights: • The inverse problem was solved for finding zero velocity isolines of magnetically modified biological cells. • Solution of the inverse problem depends on the size of cells and the number of nanoparticles attached to the single cell. • The experimental data are in agreement with theoretical solution.
Analysis of the chemical equilibrium of combustion at constant volume
Directory of Open Access Journals (Sweden)
Marius BREBENEL
2014-04-01
Full Text Available Determining the composition of a mixture of combustion gases at a given temperature is based on chemical equilibrium, when the equilibrium constants are calculated on the assumption of constant pressure and temperature. In this paper, an analysis of changes occurring when combustion takes place at constant volume is presented, deriving a specific formula of the equilibrium constant. The simple reaction of carbon combustion in pure oxygen in both cases (constant pressure and constant volume is next considered as example of application, observing the changes occurring in the composition of the combustion gases depending on temperature.
TEMPORAL MODELING OF DNA DEGRADATION IN BONE REMAINS
Directory of Open Access Journals (Sweden)
Andrei Stefan
2012-06-01
Full Text Available The aim of this study is to follow the changes that occur, in time, at DNA level and to establish an efficient and reliable protocol for ancestral DNA extraction from bones found in archaeological sites. To test whether the protocol is efficient and capable of yielding good quality DNA, extraction was first performed on fresh bones. The material consists of fresh pig (Sus scrofa and cow (Bos taurus bones that were grounded by using a drill operating at low speed. The bone powder was then incubated in lysis buffer in the presence of proteinase K. DNA isolation and purification were done by using the phenol:chloroform protocol and DNA was precipitated with absolute ethanol stored at -20oC. The extractions were carried out once every month for a total of four extractions
Instrument to determine prestress remaining in a damaged bridge girder
Civjan, Scott A.; Jirsa, James O.; Carrasquillo, Ramon L.; Fowler, David W.
1998-03-01
An instrument has been developed to estimate stress levels in prestress strands in existing members. The prototype instrument applies a lateral load to an exposed prestressing strand and measures the resulting displacements. The instrument was calibrated for 0.5-inch (12.7 mm) diameter seven-wire strand with exposed lengths of 1.5 feet (0.46 m) to 3.75 feet (1.14 m). It was tested to determine its accuracy, precision, and usefulness in the field. Strand forces were consistently estimated to within ten percent of the actual load. The device was also utilized in the placement of strand splices and was found to be more reliable in checking induced strand tensions than the standard torque wrench method.
Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical
Energy Technology Data Exchange (ETDEWEB)
Adam, Ahmad Y.; Jensen, Per, E-mail: jensen@uni-wuppertal.de [Fakultät Mathematik und Naturwissenschaften, Physikalische und Theoretische Chemie, Bergische Universität Wuppertal, D-42097 Wuppertal (Germany); Yachmenev, Andrey; Yurchenko, Sergei N. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)
2015-12-28
We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH{sub 3} radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH{sub 3} in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant’s equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role.
Ro-vibrational averaging of the isotropic hyperfine coupling constant for the methyl radical
International Nuclear Information System (INIS)
Adam, Ahmad Y.; Jensen, Per; Yachmenev, Andrey; Yurchenko, Sergei N.
2015-01-01
We present the first variational calculation of the isotropic hyperfine coupling constant of the carbon-13 atom in the CH 3 radical for temperatures T = 0, 96, and 300 K. It is based on a newly calculated high level ab initio potential energy surface and hyperfine coupling constant surface of CH 3 in the ground electronic state. The ro-vibrational energy levels, expectation values for the coupling constant, and its temperature dependence were calculated variationally by using the methods implemented in the computer program TROVE. Vibrational energies and vibrational and temperature effects for coupling constant are found to be in very good agreement with the available experimental data. We found, in agreement with previous studies, that the vibrational effects constitute about 44% of the constant’s equilibrium value, originating mainly from the large amplitude out-of-plane bending motion and that the temperature effects play a minor role
Energy Technology Data Exchange (ETDEWEB)
Lee, Kun Jai; Cho, Nam Zin; Jo, Chang Keun; Park, Chang Je; Kim, Do Sam; Park, Jeong Hwan [Korea Advanced Institute of Science and Technology, Taejon (Korea)
1999-03-01
It is probable that the issue of nuclear spent fuel and high-level waste can have negative impact on the future expansion of nuclear power programs. Accelerator-driven nuclear waste transmutation with constant composition TRU feeding which satisfies non-proliferation condition will help establish the long-range nuclear waste disposal strategy. In this study, current status of accelerator-driven transmutation of waste technology, and feasibility analysis of constant composition TRU feeding system were investigated. We ascertained that solid system using constant composition TRU is feasible with the the capability of transmutation. (author). 13 refs., 53 figs., 20 tabs.
Supersymmetric large extra dimensions and the cosmological constant: an update
International Nuclear Information System (INIS)
Burgess, C.P.
2004-01-01
This article critically reviews the proposal for addressing the cosmological constant problem within the framework of supersymmetric large extra dimensions (SLED), as recently proposed in hep-th/0304256. After a brief restatement of the cosmological constant problem, a short summary of the proposed mechanism is given. The emphasis is on the perspective of the low-energy effective theory in order to see how it addresses the problem of why low-energy particles like the electron do not contribute too large a vacuum energy. This is followed by a discussion of the main objections, which are grouped into the following five topics: (1) Weinberg's No-Go Theorem. (2) Are hidden tunings of the theory required, and are these stable under renormalization? (3) Why should the mechanism apply only now and not rule out possible earlier epochs of inflationary dynamics? (4) How big are quantum effects, and which are the most dangerous? and (5) Even if successful, can the mechanism be consistent with cosmological or current observational constraints? It is argued that there are plausible reasons why the mechanism can thread the potential objections, but that a definitive proof that it does depends on addressing well-defined technical points. These points include identifying what fixes the size of the extra dimensions, checking how topological obstructions renormalize and performing specific calculations of quantum corrections. More detailed studies of these issues, which are well within reach of our present understanding of extra-dimensional theories, are currently underway. As such, the jury remains out concerning the proposal, although the prospects for acquittal still seem good. (An abridged version of this article appears in the proceedings of SUSY 2003.)
Why silicon is and will remain the dominant photovoltaic material
Singh, Rajendra
2009-07-01
Rising demands of energy in emerging economies, coupled with the green house gas emissions related problems around the globe have provided a unique opportunity of exploiting the advantages offered by photovoltaic (PV) systems for green energy electricity generation. Similar to cell phones, power generated by PV systems can reach over two billion people worldwide who have no access to clean energy. Only silicon based PV devices meet the low-cost manufacturing criterion of clean energy conversion (abundance of raw material and no environmental health and safety issues). The use of larger size glass substrates and manufacturing techniques similar to the ones used by the liquid crystal display industry and the large scale manufacturing of amorphous silicon thin films based modules (~ GW per year manufacturing at a single location) can lead to installed PV system cost of $3/Wp. This will open a huge market for grid connected PV systems and related markets. With further research and development, this approach can provide $2/Wp installed PV system costs in the next few years. At this cost level, PV electricity generation is competitive with any other technology, and PV power generation can be a dominant electricity generation technology in the 21st century.
Genetic transformation of fruit trees: current status and remaining challenges.
Gambino, Giorgio; Gribaudo, Ivana
2012-12-01
Genetic transformation has emerged as a powerful tool for genetic improvement of fruit trees hindered by their reproductive biology and their high levels of heterozygosity. For years, genetic engineering of fruit trees has focussed principally on enhancing disease resistance (against viruses, fungi, and bacteria), although there are few examples of field cultivation and commercial application of these transgenic plants. In addition, over the years much work has been performed to enhance abiotic stress tolerance, to induce modifications of plant growth and habit, to produce marker-free transgenic plants and to improve fruit quality by modification of genes that are crucially important in the production of specific plant components. Recently, with the release of several genome sequences, studies of functional genomics are becoming increasingly important: by modification (overexpression or silencing) of genes involved in the production of specific plant components is possible to uncover regulatory mechanisms associated with the biosynthesis and catabolism of metabolites in plants. This review focuses on the main advances, in recent years, in genetic transformation of the most important species of fruit trees, devoting particular attention to functional genomics approaches and possible future challenges of genetic engineering for these species in the post-genomic era.
The road ahead, what remains to be done
International Nuclear Information System (INIS)
Heinonen, O.
1999-01-01
High priority is given to work on integrating the traditional nuclear material verification activities with the new strengthening safeguards measures. The aim is to optimize the combination of all safeguards measures available to the Agency in order to achieve maximum effectiveness and efficiency within available resources. The scope for integration is expected to be greatest in States with substantial nuclear fuel cycles and where both safeguards agreements and additional protocols are in force. The work on integration is focused on such situations. The Secretariat is elaborating a strategy and co-ordination plan for the development of integrated safeguards that reflects advice provided by the Standing Advisory Group on Safeguards Implementation (SAGSI) and takes into account the results of a consultants meeting on integrated safeguards held in December 1998. The consultants underlined that key role of State evaluation activities in integrated safeguards that will form an objective basis for the elaboration of State level approaches. Appropriate co-ordination by the Department of Safeguards is being maintained with related activities in the Secretariat and in Member States within the framework of the Agency's Safeguards Research and Development and Implementation Support Programme. (author)
The road ahead, what remains to be done
Energy Technology Data Exchange (ETDEWEB)
Heinonen, O. [International Atomic Energy Agency, Division of Operations A, Vienna (Austria)
1999-07-01
High priority is given to work on integrating the traditional nuclear material verification activities with the new strengthening safeguards measures. The aim is to optimize the combination of all safeguards measures available to the Agency in order to achieve maximum effectiveness and efficiency within available resources. The scope for integration is expected to be greatest in States with substantial nuclear fuel cycles and where both safeguards agreements and additional protocols are in force. The work on integration is focused on such situations. The Secretariat is elaborating a strategy and co-ordination plan for the development of integrated safeguards that reflects advice provided by the Standing Advisory Group on Safeguards Implementation (SAGSI) and takes into account the results of a consultants meeting on integrated safeguards held in December 1998. The consultants underlined that key role of State evaluation activities in integrated safeguards that will form an objective basis for the elaboration of State level approaches. Appropriate co-ordination by the Department of Safeguards is being maintained with related activities in the Secretariat and in Member States within the framework of the Agency's Safeguards Research and Development and Implementation Support Programme. (author)
The Remains of the Day in Dissociative Amnesia
Directory of Open Access Journals (Sweden)
Angelica Staniloiu
2012-04-01
Full Text Available Memory is not a unity, but is divided along a content axis and a time axis, respectively. Along the content dimension, five long-term memory systems are described, according to their hierarchical ontogenetic and phylogenetic organization. These memory systems are assumed to be accompanied by different levels of consciousness. While encoding is based on a hierarchical arrangement of memory systems from procedural to episodic-autobiographical memory, retrieval allows independence in the sense that no matter how information is encoded, it can be retrieved in any memory system. Thus, we illustrate the relations between various long-term memory systems by reviewing the spectrum of abnormalities in mnemonic processing that may arise in the dissociative amnesia—a condition that is usually characterized by a retrieval blockade of episodic-autobiographical memories and occurs in the context of psychological trauma, without evidence of brain damage on conventional structural imaging. Furthermore, we comment on the functions of implicit memories in guiding and even adaptively molding the behavior of patients with dissociative amnesia and preserving, in the absence of autonoetic consciousness, the so-called “internal coherence of life”.
Bondi mass with a cosmological constant
Saw, Vee-Liem
2018-04-01
The mass loss of an isolated gravitating system due to energy carried away by gravitational waves with a cosmological constant Λ ∈R was recently worked out, using the Newman-Penrose-Unti approach. In that same article, an expression for the Bondi mass of the isolated system, MΛ, for the Λ >0 case was proposed. The stipulated mass MΛ would ensure that in the absence of any incoming gravitational radiation from elsewhere the emitted gravitational waves must carry away a positive-definite energy. That suggested quantity, however, introduced a Λ -correction term to the Bondi mass MB (where MB is the usual Bondi mass for asymptotically flat spacetimes), which would involve information not just on the state of the system at that moment but ostensibly also its past history. In this paper, we derive the identical mass-loss equation using an integral formula on a hypersurface formulated by Frauendiener based on the Nester-Witten identity and argue that one may adopt a generalization of the Bondi mass with Λ ∈R without any correction, viz., MΛ=MB for any Λ ∈R . Furthermore, with MΛ=MB, we show that for purely quadrupole gravitational waves given off by the isolated system (i.e., when the "Bondi news" σo comprises only the l =2 components of the spherical harmonics with spin-weight 2) the energy carried away is manifestly positive definite for the Λ >0 case. For a general σo having higher multipole moments, this perspicuous property in the Λ >0 case still holds if those l >2 contributions are weak—more precisely, if they satisfy any of the inequalities given in this paper.
Computing the Gromov hyperbolicity constant of a discrete metric space
Ismail, Anas
2012-01-01
, and many other areas of research. The Gromov hyperbolicity constant of several families of graphs and geometric spaces has been determined. However, so far, the only known algorithm for calculating the Gromov hyperbolicity constant δ of a discrete metric
Tampubolon, Marojahan; Pamungkas, Laskar; Hsieh, Yao Ching; Chiu, Huang Jen
2018-04-01
This paper presents the implementation of Constant Voltage (CV) and Constant Current (CC) control for a wireless charger system. A battery charging system needs these control modes to ensure the safety of the battery and the effectiveness of the charging system. Here, the wireless charger system does not employ any post-regulator stage to control the output voltage and output current of the charger. But, it uses a variable frequency control incorporated with a conventional PI control. As a result, the size and the weight of the system are reduced. This paper discusses the brief review of the SS-WPT, control strategy and implementation of the CV and CC control. Experimental hardware with 2kW output power has been performed and tested. The results show that the proposed CV and CC control method works well with the system.
Chemical Plants Remain Vulnerable to Terrorists: A Call to Action
Lippin, Tobi Mae; McQuiston, Thomas H.; Bradley-Bull, Kristin; Burns-Johnson, Toshiba; Cook, Linda; Gill, Michael L.; Howard, Donna; Seymour, Thomas A.; Stephens, Doug; Williams, Brian K.
2006-01-01
U.S. chemical plants currently have potentially catastrophic vulnerabilities as terrorist targets. The possible consequences of these vulnerabilities echo from the tragedies of the Bhopal incident in 1984 to the terrorist attacks on 11 September 2001 and, most recently, Hurricanes Katrina and Rita. Findings from a 2004 nationwide participatory research study of 125 local union leaders at sites with very large volumes of highly hazardous chemicals suggest that voluntary efforts to achieve chemical plant security are not succeeding. Study respondents reported that companies had only infrequently taken actions that are most effective in preventing or in preparing to respond to a terrorist threat. In addition, companies reportedly often failed to involve key stakeholders, including workers, local unions, and the surrounding communities, in these efforts. The environmental health community thus has an opportunity to play a key role in advocating for and supporting improvements in prevention of and preparation for terrorist attacks. Policy-level recommendations to redress chemical site vulnerabilities and the related ongoing threats to the nation’s security are as follows: a) specify detailed requirements for chemical site assessment and security; b) mandate audit inspections supported by significant penalties for cases of noncompliance; c) require progress toward achieving inherently safer processes, including the minimizing of storage of highly hazardous chemicals; d) examine and require additional effective actions in prevention, emergency preparedness, and response and remediation; e) mandate and fund the upgrading of emergency communication systems; and f) involve workers and community members in plan creation and equip and prepare them to prevent and respond effectively to an incident. PMID:16966080
2011-03-15
...: University of Wyoming, Anthropology Department, Human Remains Repository, Laramie, WY AGENCY: National Park... Anthropology Department, Human Remains Repository, Laramie, WY. The human remains and associated funerary... the human remains was made by University of Wyoming, Anthropology Department, Human Remains Repository...
Unger, K A; Watterson, J H
2016-10-01
The effects of decomposition microclimate on the distribution of dextromethorphan (DXM) and dextrorphan (DXT) in skeletonized remains of rats acutely exposed to DXM were examined. Animals (n = 10) received DXM (75 mg/kg, i.p.), were euthanized 30 min post-dose and immediately allowed to decompose at either Site A (shaded forest microenvironment on a grass-covered soil substrate) or Site B (rocky substrate exposed to direct sunlight, 600 m from Site A). Ambient temperature and relative humidity were automatically recorded 3 cm above rats at each site. Skeletal elements (vertebral columns, ribs, pelvic girdles, femora, tibiae, humeri and scapulae) were harvested, and analyzed using microwave assisted extraction, microplate solid phase extraction, and GC/MS. Drug levels, expressed as mass-normalized response ratios, and the ratios of DXT and DXM levels were compared across bones and between microclimate sites. No significant differences in DXT levels or metabolite/parent ratios were observed between sites or across bones. Only femoral DXM levels differed significantly between microclimate sites. For pooled data, microclimate was not observed to significantly affect analyte levels, nor the ratio of levels of DXT and DXM. These data suggest that microclimate conditions do not influence DXM and metabolite distribution in skeletal remains. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Constant curvature black holes in Einstein AdS gravity: Euclidean action and thermodynamics
Guilleminot, Pablo; Olea, Rodrigo; Petrov, Alexander N.
2018-03-01
We compute the Euclidean action for constant curvature black holes (CCBHs), as an attempt to associate thermodynamic quantities to these solutions of Einstein anti-de Sitter (AdS) gravity. CCBHs are gravitational configurations obtained by identifications along isometries of a D -dimensional globally AdS space, such that the Riemann tensor remains constant. Here, these solutions are interpreted as extended objects, which contain a (D -2 )-dimensional de-Sitter brane as a subspace. Nevertheless, the computation of the free energy for these solutions shows that they do not obey standard thermodynamic relations.
International Nuclear Information System (INIS)
2001-02-01
This report contains translations of eleven papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 2, 1999). They are marked as ''Translated from Russian''. Four original papers published in YK in English are included with correction of found misprints and small format changes. As a result the report contains all papers presented in YK, 2 (1999). (author)
International Nuclear Information System (INIS)
2002-12-01
This report contains translations of eight papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 1, 2001). They are marked as 'Translated from Russian'. Six original papers published in YK in English are included with correction of found misprints and small format changes. As a result the report contains all papers presented in YK, 1 (2001). (author)
Energy Technology Data Exchange (ETDEWEB)
NONE
2001-10-01
This report contains translations of five papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 2, 2000). They are marked as 'Translated from Russian'. Two original papers published in YK in English are included with correction of found misprints and small format changes. As a result, the report contains all papers presented in YK, 2 (2000). (author)
International Nuclear Information System (INIS)
2001-12-01
This report contains translations of seven papers published in the Nuclear Constants journal (Voprosy Atomnoj Nauki I Teknniki, seriya: Yadernye Konstanty (YK), vypusk 1, 2000). They are marked as 'Translated from Russian'. Two original papers published in YK in English are included with correction of found misprints and small format changes. As a result the report contains all papers presented in YK, 1 (2000). (author)
Determination of constants of factorized pairing force from conservation laws
International Nuclear Information System (INIS)
Voronkov, Yu.P.; Mikhajlov, V.M.
1975-01-01
The constants of a factorized interaction in the particle-particle channel are evaluated on the basis of average field parameters and Cooper pairing. The relations between the constants of multipole particle-particle forces are derived for the spherical nuclei. The constants of the quadrupole pairing are obtained for deformed nuclei from the angular momentum conservation law. The calculated constants are compared with empiricalones
The fine-structure constant before quantum mechanics
International Nuclear Information System (INIS)
Kragh, Helge
2003-01-01
This paper focuses on the early history of the fine-structure constant, largely the period until 1925. Contrary to what is generally assumed, speculations concerning the interdependence of the elementary electric charge and Planck's constant predated Arnold Sommerfeld's 1916 discussion of the dimensionless constant. This paper pays particular attention to a little known work from 1914 in which G N Lewis and E Q Adams derived what is effectively a numerical expression for the fine-structure constant
Dual power, constant speed electric motor system
Kirschbaum, H.S.
1984-07-31
A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level. 6 figs.
Dual power, constant speed electric motor system
Kirschbaum, Herbert S.
1984-01-01
A dual capacity permanent split capacitor electric motor system is provided with a stator having main and auxiliary windings. The main stator winding includes two winding sections which are connected in parallel with each other and across a pair of line terminals while the auxiliary winding is connected in series with a capacitor to form a circuit branch which is connected between the line terminals for operation at a first output power level. Switching means are provided to reconnect the main stator winding sections in series with each other and in series with a second capacitor to form a circuit branch which is connected between the line terminals while the stator auxiliary winding is connected directly between the line terminals for operation at a second output power level. Automatic rotation reversal occurs when the motor switches from the first to the second output power level.
Association constants of telluronium salts; Konstanty assotsiatsii telluronievykh solej
Energy Technology Data Exchange (ETDEWEB)
Kovach, N A; Rivkin, B B; Sadekov, T D; Shvajka, O P
1997-12-31
Association constants in acetonitrile of triphenyl telluronium salts, which are dilute electrolytes, are determined through the conductometry method. Satisfactory correlation dependence of constants of interion association and threshold molar electroconductivity on the Litvinenko-Popov constants for depositing groups is identified. 6 refs.
Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide
DEFF Research Database (Denmark)
Kjær, Hanna; Nielsen, Monia R.; Pagola, Gabriel I.
2012-01-01
In this paper we present the so far most extended investigation of the calculation of the coupling constant polarizability of a molecule. The components of the coupling constant polarizability are derivatives of the NMR indirect nuclear spin-spin coupling constant with respect to an external elec...
Towards Grothendieck constants and LHV models in quantum mechanics
International Nuclear Information System (INIS)
Hua, Bobo; Li, Ming; Zhang, Tinggui; Zhou, Chunqin; Li-Jost, Xianqing; Fei, Shao-Ming
2015-01-01
We adopt a continuous model to estimate the Grothendieck constants. An analytical formula to compute the lower bounds of Grothendieck constants has been explicitly derived for arbitrary orders, which improves previous bounds. Moreover, our lower bound of the Grothendieck constant of order three gives a refined bound of the threshold value for the nonlocality of the two-qubit Werner states. (paper)
Reliability concerns with logical constants in Xilinx FPGA designs
Energy Technology Data Exchange (ETDEWEB)
Quinn, Heather M [Los Alamos National Laboratory; Graham, Paul [Los Alamos National Laboratory; Morgan, Keith [Los Alamos National Laboratory; Ostler, Patrick [Los Alamos National Laboratory; Allen, Greg [JPL; Swift, Gary [XILINX; Tseng, Chen W [XILINX
2009-01-01
In Xilinx Field Programmable Gate Arrays logical constants, which ground unused inputs and provide constants for designs, are implemented in SEU-susceptible logic. In the past, these logical constants have been shown to cause the user circuit to output bad data and were not resetable through off-line rcconfiguration. In the more recent devices, logical constants are less problematic, though mitigation should still be considered for high reliability applications. In conclusion, we have presented a number of reliability concerns with logical constants in the Xilinx Virtex family. There are two main categories of logical constants: implicit and explicit logical constants. In all of the Virtex devices, the implicit logical constants are implemented using half latches, which in the most recent devices are several orders of magnitudes smaller than configuration bit cells. Explicit logical constants are implemented exclusively using constant LUTs in the Virtex-I and Virtex-II, and use a combination of constant LUTs and architectural posts to the ground plane in the Virtex-4. We have also presented mitigation methods and options for these devices. While SEUs in implicit and some types of explicit logical constants can cause data corrupt, the chance of failure from these components is now much smaller than it was in the Virtex-I device. Therefore, for many cases, mitigation might not be necessary, except under extremely high reliability situations.
Stability constant of the trisglycinto metal complexes | Na'aliya ...
African Journals Online (AJOL)
The stability constants of iron, manganese, cobalt, and nickel complexes of glycine have been determined in aqueous solution by potentiometric titration with standard sodium hydroxide solution. The values of the stepwise stability constants were obtained by ORIGIN '50' program. The overall stability constants of the ...
DFT computations of the lattice constant, stable atomic structure and ...
African Journals Online (AJOL)
This paper presents the most stable atomic structure and lattice constant of Fullerenes (C60). FHI-aims DFT code was used to predict the stable structure and the computational lattice constant of C60. These were compared with known experimental structures and lattice constants of C60. The results obtained showed that ...
Some comments on the universal constant in DSR
Energy Technology Data Exchange (ETDEWEB)
Girelli, Florian [SISSA, Via Beirut 2-4, 34014 Trieste (Italy); INFN, Sezione di Trieste (Italy); Livine, Etera R [Laborat. de Physique, ENS Lyon, CNRS UMR 5672, 46 Allee d' Italie, 69364 Lyon Cedex 07 (France)
2007-05-15
Deformed Special Relativity is usually presented as a deformation of Special Relativity accommodating a new universal constant, the Planck mass, while respecting the relativity principle. In order to avoid some fundamental problems (e.g. soccer ball problem), we argue that we should switch point of view and consider instead the Newton constant G as the universal constant.
Some comments on the universal constant in DSR
International Nuclear Information System (INIS)
Girelli, Florian; Livine, Etera R
2007-01-01
Deformed Special Relativity is usually presented as a deformation of Special Relativity accommodating a new universal constant, the Planck mass, while respecting the relativity principle. In order to avoid some fundamental problems (e.g. soccer ball problem), we argue that we should switch point of view and consider instead the Newton constant G as the universal constant
Stability constants of the Europium complexes with the chloride ions
International Nuclear Information System (INIS)
Jimenez R, M.; Solache R, M.; Rojas H, A.
2000-01-01
The stability constants of lanthanides complexes with chloride ions which were determined at the same ionic force but in different media, are significantly different. It does not exist a systematic study over these stability constants. The purpose of this work is to determine the stability constants of the europium complexes with chloride ions at 303 K, by the solvents extraction method. (Author)
Garbage-free reversible constant multipliers for arbitrary integers
DEFF Research Database (Denmark)
Mogensen, Torben Ægidius
2013-01-01
We present a method for constructing reversible circuitry for multiplying integers by arbitrary integer constants. The method is based on Mealy machines and gives circuits whose size are (in the worst case) linear in the size of the constant. This makes the method unsuitable for large constants...
Beauty vector meson decay constants from QCD sum rules
Energy Technology Data Exchange (ETDEWEB)
Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)
2016-01-22
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
The equivalence principle and the gravitational constant in experimental relativity
International Nuclear Information System (INIS)
Spallicci, A.D.A.M.
1988-01-01
Fischbach's analysis of the Eotvos experiment, showing an embedded fifth force, has stressed the importance of further tests of the Equivalence Principle (EP). From Galilei and Newton, the EP played the role of a postulate for all gravitational physics and mechanics (weak EP), until Einstein, who extended the validity of the EP to all physics (strong EP). After Fischbach's publication on the fifth force, several experiments have been performed or simply proposed to test the WEP. They are concerned with possible gravitational potential anomalies, depending upon distances or matter composition. While the low level of accuracy with which the gravitational constant G is known has been recognized, experiments have been proposed to test G in the range from few cm until 200 m. This paper highlights the different features of the proposed space experiments. Possible implications on the metric formalism for objects in low potential and slow motion are briefly indicated
The case for the cosmological constant
Indian Academy of Sciences (India)
A time dependent cosmological A-term can be generated by scalar field ... Perlmutter et al (1999) indicate that the joint probability distribution of ΩС ΩA is well .... and С must be adjusted to very high levels of accuracy in order to ensure. С.
How does pressure gravitate? Cosmological constant problem confronts observational cosmology
Narimani, Ali; Afshordi, Niayesh; Scott, Douglas
2014-08-01
An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 σ level. However, including higher resolution CMB observations (``highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 σ level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ζ4 = 0.105 ± 0.049 (+highL CMB), or ζ4 = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ΛCDM including tensors, with 0ζ4=), and also among different data sets.
How does pressure gravitate? Cosmological constant problem confronts observational cosmology
International Nuclear Information System (INIS)
Narimani, Ali; Scott, Douglas; Afshordi, Niayesh
2014-01-01
An important and long-standing puzzle in the history of modern physics is the gross inconsistency between theoretical expectations and cosmological observations of the vacuum energy density, by at least 60 orders of magnitude, otherwise known as the cosmological constant problem. A characteristic feature of vacuum energy is that it has a pressure with the same amplitude, but opposite sign to its energy density, while all the precision tests of General Relativity are either in vacuum, or for media with negligible pressure. Therefore, one may wonder whether an anomalous coupling to pressure might be responsible for decoupling vacuum from gravity. We test this possibility in the context of the Gravitational Aether proposal, using current cosmological observations, which probe the gravity of relativistic pressure in the radiation era. Interestingly, we find that the best fit for anomalous pressure coupling is about half-way between General Relativity (GR), and Gravitational Aether (GA), if we include Planck together with WMAP and BICEP2 polarization cosmic microwave background (CMB) observations. Taken at face value, this data combination excludes both GR and GA at around the 3 σ level. However, including higher resolution CMB observations (''highL'') or baryonic acoustic oscillations (BAO) pushes the best fit closer to GR, excluding the Gravitational Aether solution to the cosmological constant problem at the 4- 5 σ level. This constraint effectively places a limit on the anomalous coupling to pressure in the parametrized post-Newtonian (PPN) expansion, ζ 4 = 0.105 ± 0.049 (+highL CMB), or ζ 4 = 0.066 ± 0.039 (+BAO). These represent the most precise measurement of this parameter to date, indicating a mild tension with GR (for ΛCDM including tensors, with 0ζ 4 =), and also among different data sets
International Nuclear Information System (INIS)
Zanzi, Andrea
2010-01-01
The chameleonic behavior of the string theory dilaton is suggested. Some of the possible consequences of the chameleonic string dilaton are analyzed in detail. In particular, (1) we suggest a new stringy solution to the cosmological constant problem and (2) we point out the nonequivalence of different conformal frames at the quantum level. In order to obtain these results, we start taking into account the (strong coupling) string loop expansion in the string frame (S-frame), therefore the so-called form factors are present in the effective action. The correct dark energy scale is recovered in the Einstein frame (E-frame) without unnatural fine-tunings and this result is robust against all quantum corrections, granted that we assume a proper structure of the S-frame form factors in the strong coupling regime. At this stage, the possibility still exists that a certain amount of fine-tuning may be required to satisfy some phenomenological constraints. Moreover in the E-frame, in our proposal, all the interactions are switched off on cosmological length scales (i.e., the theory is IR-free), while higher derivative gravitational terms might be present locally (on short distances) and it remains to be seen whether these facts clash with phenomenology. A detailed phenomenological analysis is definitely necessary to clarify these points.
The cosmological constant in theories with finite spacetime
International Nuclear Information System (INIS)
Kummer, Janis
2014-08-01
We study the role of the cosmological constant in different theories with finite spacetime. The cosmological constant appears both as an initial condition and as a constant of integration. In the context of the cosmological constant problem a new model will be presented. This modification of general relativity generates a small, non-vanishing cosmological constant, which is radiatively stable. The dynamics of the expansion of the universe in this model will be analyzed. Eventually, we try to solve the emergent problems concerning the generation of accelerated expansion using a quintessence model of dark energy.
Constant-roll tachyon inflation and observational constraints
Gao, Qing; Gong, Yungui; Fei, Qin
2018-05-01
For the constant-roll tachyon inflation, we derive the analytical expressions for the scalar and tensor power spectra, the scalar and tensor spectral tilts and the tensor to scalar ratio to the first order of epsilon1 by using the method of Bessel function approximation. The derived ns-r results are compared with the observations, we find that only the constant-roll inflation with ηH being a constant is consistent with the observations and observations constrain the constant-roll inflation to be slow-roll inflation. The tachyon potential is also reconstructed for the constant-roll inflation which is consistent with the observations.
Legal reality of Russia: constants and variables
Directory of Open Access Journals (Sweden)
Andrey Valeryevich Skorobogatov
2015-06-01
Full Text Available Objective to develop the sciencebased knowledge about essential and substantial aspects of the current legal reality of Russia in the context of postclassical paradigm. Methods the methodological basis of this research is the synthesis of classical and postclassical paradigms that determine the choice of specific methods of research formallegal comparative legal modeling method hermeneutic discursive methods. Results basing on the postclassical methodology it is proved that the legal reality of Russia consists of three levels legislation law enforcement and legal behavior. The determinant level of legal reality is legal behavior that is aimed at observing the unwritten rules. The legal reality of Russia is characterized by a transgressive state of the modern Russian society expressed in broad application of nonlegislative nonlegal practices low level of legal culture legal nihilism and legal infantilism. Scientific novelty the article for the first time analyzes the ontological and phenomenological essence of the legal reality in Russia and determines its transgressive nature at the present stage of development. Practical value the main provisions and conclusions of the article can be used in scientific and pedagogical activity when considering questions about the nature and content of legal development. nbsp
Multiple constant multiplication optimizations for field programmable gate arrays
Kumm, Martin
2016-01-01
This work covers field programmable gate array (FPGA)-specific optimizations of circuits computing the multiplication of a variable by several constants, commonly denoted as multiple constant multiplication (MCM). These optimizations focus on low resource usage but high performance. They comprise the use of fast carry-chains in adder-based constant multiplications including ternary (3-input) adders as well as the integration of look-up table-based constant multipliers and embedded multipliers to get the optimal mapping to modern FPGAs. The proposed methods can be used for the efficient implementation of digital filters, discrete transforms and many other circuits in the domain of digital signal processing, communication and image processing. Contents Heuristic and ILP-Based Optimal Solutions for the Pipelined Multiple Constant Multiplication Problem Methods to Integrate Embedded Multipliers, LUT-Based Constant Multipliers and Ternary (3-Input) Adders An Optimized Multiple Constant Multiplication Architecture ...
Long persistence of rigor mortis at constant low temperature.
Varetto, Lorenzo; Curto, Ombretta
2005-01-06
We studied the persistence of rigor mortis by using physical manipulation. We tested the mobility of the knee on 146 corpses kept under refrigeration at Torino's city mortuary at a constant temperature of +4 degrees C. We found a persistence of complete rigor lasting for 10 days in all the cadavers we kept under observation; and in one case, rigor lasted for 16 days. Between the 11th and the 17th days, a progressively increasing number of corpses showed a change from complete into partial rigor (characterized by partial bending of the articulation). After the 17th day, all the remaining corpses showed partial rigor and in the two cadavers that were kept under observation "à outrance" we found the absolute resolution of rigor mortis occurred on the 28th day. Our results prove that it is possible to find a persistence of rigor mortis that is much longer than the expected when environmental conditions resemble average outdoor winter temperatures in temperate zones. Therefore, this datum must be considered when a corpse is found in those environmental conditions so that when estimating the time of death, we are not misled by the long persistence of rigor mortis.
Mols, G; Kessler, V; Benzing, A; Lichtwarck-Aschoff, M; Geiger, K; Guttmann, J
2001-02-01
When managing patients with acute respiratory distress syndrome (ARDS), respiratory system compliance is usually considered first and changes in resistance, although recognized, are neglected. Resistance can change considerably between minimum and maximum lung volume, but is generally assumed to be constant in the tidal volume range (V(T)). We measured resistance during tidal ventilation in 16 patients with ARDS or acute lung injury by the slice method and multiple linear regression analysis. Resistance was constant within V(T) in only six of 16 patients. In the remaining patients, resistance decreased, increased or showed complex changes. We conclude that resistance within V(T) varies considerably from patient to patient and that constant resistance within V(T) is not always likely.
Strydom, Reuben; Srinivasan, Mandyam V
2017-09-21
The aim of this study is to derive a guidance law by which an unmanned aerial system(s) (UAS) can pursue a moving target at a constant distance, while concealing its own motion. We derive a closed-form solution for the trajectory of the UAS by imposing two key constraints: (1) the shadower moves in such a way as to be perceived as a stationary object by the shadowee, and (2) the distance between the shadower and shadowee is kept constant. Additionally, the theory presented in this paper considers constraints on the maximum achievable speed and acceleration of the shadower. Our theory is tested through Matlab simulations, which validate the camouflage strategy for both 2D and 3D conditions. Furthermore, experiments using a realistic vision-based implementation are conducted in a virtual environment, where the results demonstrate that even with noisy state information it is possible to remain well camouflaged using the constant distance motion camouflage technique.
Directory of Open Access Journals (Sweden)
Jussara Bertho Fantinatti
2007-01-01
Full Text Available This work aimed to analyse Eucalyptus grandis W.Hill ex Maiden seed behaviour, under controlled deterioration, and to estimate viability equation constants for the species. Seeds were harvested in the growing season of 1999, and the moisture contents were adjusted from 11.3% to a range between 1.2 and 18.1% at 25ºC. The subsamples were sealed into laminate aluminium-foil packets, for storage in incubators at 40, 50 and 65±0.5ºC. The seeds presented orthodox performance, in which the constants for predicting seed longevity of E. grandis were K E = 9.661, C W = 6.467, C H = 0.03498 and C Q = 0.0002330. The usual and inverse relationship between water content and seed longevity was also observed. The lowest moisture content limit for application of the viability equation at 65ºC was 4.9%, estimated under hygroscopic equilibrium with 23% of relative humidity in the storage environment.Este trabalho teve como objetivos verificar o desempenho de sementes de Eucalyptus grandis W.Hill ex Maiden, após a deterioração em condições controladas, e obter as constantes da equação de viabilidade. As sementes foram colhidas na safra de 1999, e a umidade foi ajustada de 11,3% para valores entre 1,2 e 18,1% a 25ºC As subamostras foram acondicionadas em embalagens de alumínio termossoldadas, armazenadas a 40, 50 e 65±0,5ºC. As sementes apresentaram um desempenho ortodoxo em relação ao armazenamento. As constantes para a predição da longevidade foram K E = 9,661, C W = 6,467, C H = 0,03498 e C Q = 0,0002330. Foi observada a relação inversa entre teor de água e longevidade. O limite inferior de grau de umidade, calculado para aplicação da equação a 65ºC, foi de 4,9%, estimativa obtida sob equilíbrio higroscópico com umidade relativa de 23% no ambiente de armazenamento.
Tailoring automatic exposure control toward constant detectability in digital mammography.
Salvagnini, Elena; Bosmans, Hilde; Struelens, Lara; Marshall, Nicholas W
2015-07-01
The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. The default "opdose" AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d'), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (Tt) in the European guidelines for the 0.1 mm diameter disc (i.e., Tt ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (Tt), calculated detectability (d'), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. The default opdose AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d' 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d'), respectively. Threshold gold thickness (0.1 mm diameter disc) for the default
Tailoring automatic exposure control toward constant detectability in digital mammography
Energy Technology Data Exchange (ETDEWEB)
Salvagnini, Elena, E-mail: elena.salvagnini@uzleuven.be [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Bosmans, Hilde [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium); Struelens, Lara [SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Marshall, Nicholas W. [Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium)
2015-07-15
Purpose: The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. Methods: The default “OPDOSE” AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d′), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (T{sub t}) in the European guidelines for the 0.1 mm diameter disc (i.e., T{sub t} ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (T{sub t}), calculated detectability (d′), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. Results: The default OPDOSE AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d′ 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d′), respectively
Analysis of constant-head well tests in nonporous fractured rock
International Nuclear Information System (INIS)
Doe, T.; Remer, J.
1981-01-01
If one compares the results of steady analyses and transient flowrate analyses, the error in assuming steady flow is less than an order of magnitude for reasonable values of storativity, and this error can be minimized through proper choice of radius of influence. Although the steady flow assumptions do not result in large errors in the calculation of permeability, careful design of constant-head well tests can yield not only storativity, but also qualitative information on the areal extent of permeable zones or fractures tested. Constant-head well tests have several major advantages over other well test techniques in low permeability rock. Unlike pump tests, wellbore storage effects are virtually nonexistant. Provided low-flow measurement apparatus is available, constant-level tests are far more rapid than slug tests and, unlike pulse tests, compliance of equipment is not a factor, since the system is maintained at constant pressure throughout the test
Grün, Rainer; Spooner, Nigel; Magee, John; Thorne, Alan; Simpson, John; Yan, Ge; Mortimer, Graham
2011-05-01
We present a detailed description of the geological setting of the burial site of the WLH 50 human remains along with attempts to constrain the age of this important human fossil. Freshwater shells collected at the surface of Unit 3, which is most closely associated with the human remains, and a carbonate sample that encrusted the human bone were analysed. Gamma spectrometry was carried out on the WLH 50 calvaria and TIMS U-series analysis on a small post-cranial bone fragment. OSL dating was applied to a sample from Unit 3 at a level from which the WLH 50 remains may have eroded, as well as from the underlying sediments. Considering the geochemistry of the samples analysed, as well as the possibility of reworking or burial from younger layers, the age of the WLH 50 remains lies between 12.2 ± 1.8 and 32.8 ± 4.6 ka (2-σ errors). Copyright © 2010 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
S. D. Deosarkar
2012-01-01
Full Text Available The proton-ligand stability constants of some biologically important new pyrazoles and formation constants of their complexes with Ni(II were determined at 0.1 mol dm-3 ionic strength and at 303.15 K in different dielectric constant of dioxane-water mixture by potentiometric method. The Calvin-Bjerrum's pH-titration technique as used by Irving and Rossotti was used for determination of stability constants. The results enabled to study the electrostatic forces of attraction between metal ion and ligand with changes in dielectric constant of the medium.
Quintessential inflation from a variable cosmological constant in a 5D vacuum
Membiela, Agustin; Bellini, Mauricio
2006-01-01
We explore an effective 4D cosmological model for the universe where the variable cosmological constant governs its evolution and the pressure remains negative along all the expansion. This model is introduced from a 5D vacuum state where the (space-like) extra coordinate is considered as noncompact. The expansion is produced by the inflaton field, which is considered as nonminimally coupled to gravity. We conclude from experiental data that the coupling of the inflaton with gravity should be...
Temperature dependence of grain boundary free energy and elastic constants
International Nuclear Information System (INIS)
Foiles, Stephen M.
2010-01-01
This work explores the suggestion that the temperature dependence of the grain boundary free energy can be estimated from the temperature dependence of the elastic constants. The temperature-dependent elastic constants and free energy of a symmetric Σ79 tilt boundary are computed for an embedded atom method model of Ni. The grain boundary free energy scales with the product of the shear modulus times the lattice constant for temperatures up to about 0.75 the melting temperature.
On Riemannian manifolds (Mn, g) of quasi-constant curvature
International Nuclear Information System (INIS)
Rahman, M.S.
1995-07-01
A Riemannian manifold (M n , g) of quasi-constant curvature is defined. It is shown that an (M n , g) in association with other class of manifolds gives rise, under certain conditions, to a manifold of quasi-constant curvature. Some observations on how a manifold of quasi-constant curvature accounts for a pseudo Ricci-symmetric manifold and quasi-umbilical hypersurface are made. (author). 10 refs
Effects of constant voltage and constant current stress in PCBM:P3HT solar cells
DEFF Research Database (Denmark)
Cester, Andrea; Rizzo, Aldo; Bazzega, A.
2015-01-01
The aimof this work is the investigation of forward and reverse bias stress effects, cell self-heating and annealing in roll coated organic solar cells with PCBM:P3HT active layer. In reverse bias stress cells show a constant degradation over time. In forward current stress cells alternate...... mechanisms: the decrease of the net generation rate (due to formation of exciton quenching centres or the reduction of exciton separation rate); the formation of small leaky paths between anode and cathode, which reduces the total current extracted from the cell. The stress-induced damage can be recovered...... degradation and annealing phases, which are explained through the high power dissipation during the current stress, and the consequent self-heating. The high temperature is able to recover the cell performances at least until a critical temperature is reached. The degradation can be explained by the following...
An Einstein-Cartan Fine Structure Constant Definition
Directory of Open Access Journals (Sweden)
Stone R. A. Jr.
2010-01-01
Full Text Available The fine structure constant definition given in Stone R.A. Jr. Progress in Physics, 2010, v.1, 11-13 is compared to an Einstein-Cartan fine structure constant definition. It is shown that the Einstein-Cartan definition produces the correct pure theory value, just not the measure value. To produce the measured value, the pure theory Einstein-Cartan fine structure constant requires only the new variables and spin coupling of the fine structure constant definition in [1].
GRUCAL, a computer program for calculating macroscopic group constants
International Nuclear Information System (INIS)
Woll, D.
1975-06-01
Nuclear reactor calculations require material- and composition-dependent, energy averaged nuclear data to describe the interaction of neutrons with individual isotopes in material compositions of reactor zones. The code GRUCAL calculates these macroscopic group constants for given compositions from the material-dependent data of the group constant library GRUBA. The instructions for calculating group constants are not fixed in the program, but will be read at the actual execution time from a separate instruction file. This allows to accomodate GRUCAL to various problems or different group constant concepts. (orig.) [de
Directory of Open Access Journals (Sweden)
Joseph E. Peterson
2017-04-01
Full Text Available Microscopic soft tissues have been identified in fossil vertebrate remains collected from various lithologies. However, the diagenetic mechanisms to preserve such tissues have remained elusive. While previous studies have described infiltration of biofilms in Haversian and Volkmann's canals, biostratinomic alteration (e.g., trampling, and iron derived from hemoglobin as playing roles in the preservation processes, the influence of sediment texture has not previously been investigated. This study uses a Kolmogorov Smirnov Goodness-of-Fit test to explore the influence of biostratinomic variability and burial media against the infiltration of biofilms in bone samples. Controlled columns of sediment with bone samples were used to simulate burial and subsequent groundwater flow. Sediments used in this study include clay-, silt-, and sand-sized particles modeled after various fluvial facies commonly associated with fossil vertebrates. Extant limb bone samples obtained from Gallus gallus domesticus (Domestic Chicken buried in clay-rich sediment exhibit heavy biofilm infiltration, while bones buried in sands and silts exhibit moderate levels. Crushed bones exhibit significantly lower biofilm infiltration than whole bone samples. Strong interactions between biostratinomic alteration and sediment size are also identified with respect to biofilm development. Sediments modeling crevasse splay deposits exhibit considerable variability; whole-bone crevasse splay samples exhibit higher frequencies of high-level biofilm infiltration, and crushed-bone samples in modeled crevasse splay deposits display relatively high frequencies of low-level biofilm infiltration. These results suggest that sediment size, depositional setting, and biostratinomic condition play key roles in biofilm infiltration in vertebrate remains, and may influence soft tissue preservation in fossil vertebrates.
Peterson, Joseph E.; Lenczewski, Melissa E.; Clawson, Steven R.; Warnock, Jonathan P.
2017-04-01
Microscopic soft tissues have been identified in fossil vertebrate remains collected from various lithologies. However, the diagenetic mechanisms to preserve such tissues have remained elusive. While previous studies have described infiltration of biofilms in Haversian and Volkmann’s canals, biostratinomic alteration (e.g., trampling), and iron derived from hemoglobin as playing roles in the preservation processes, the influence of sediment texture has not previously been investigated. This study uses a Kolmogorov Smirnov Goodness-of-Fit test to explore the influence of biostratinomic variability and burial media against the infiltration of biofilms in bone samples. Controlled columns of sediment with bone samples were used to simulate burial and subsequent groundwater flow. Sediments used in this study include clay-, silt-, and sand-sized particles modeled after various fluvial facies commonly associated with fossil vertebrates. Extant limb bone samples obtained from Gallus gallus domesticus (Domestic Chicken) buried in clay-rich sediment exhibit heavy biofilm infiltration, while bones buried in sands and silts exhibit moderate levels. Crushed bones exhibit significantly lower biofilm infiltration than whole bone samples. Strong interactions between biostratinomic alteration and sediment size are also identified with respect to biofilm development. Sediments modeling crevasse splay deposits exhibit considerable variability; whole-bone crevasse splay samples exhibit higher frequencies of high-level biofilm infiltration, and crushed-bone samples in modeled crevasse splay deposits display relatively high frequencies of low-level biofilm infiltration. These results suggest that sediment size, depositional setting, and biostratinomic condition play key roles in biofilm infiltration in vertebrate remains, and may influence soft tissue preservation in fossil vertebrates.
Running vacuum in the Universe and the time variation of the fundamental constants of Nature
Energy Technology Data Exchange (ETDEWEB)
Fritzsch, Harald [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitaet Muenchen, Physik-Department, Munich (Germany); Sola, Joan [Nanyang Technological University, Institute for Advanced Study, Singapore (Singapore); Universitat de Barcelona, Departament de Fisica Quantica i Astrofisica, Barcelona, Catalonia (Spain); Universitat de Barcelona (ICCUB), Institute of Cosmos Sciences, Barcelona, Catalonia (Spain); Nunes, Rafael C. [Universidade Federal de Juiz de Fora, Dept. de Fisica, Juiz de Fora, MG (Brazil)
2017-03-15
We compute the time variation of the fundamental constants (such as the ratio of the proton mass to the electron mass, the strong coupling constant, the fine-structure constant and Newton's constant) within the context of the so-called running vacuum models (RVMs) of the cosmic evolution. Recently, compelling evidence has been provided that these models are able to fit the main cosmological data (SNIa+BAO+H(z)+LSS+BBN+CMB) significantly better than the concordance ΛCDM model. Specifically, the vacuum parameters of the RVM (i.e. those responsible for the dynamics of the vacuum energy) prove to be nonzero at a confidence level >or similar 3σ. Here we use such remarkable status of the RVMs to make definite predictions on the cosmic time variation of the fundamental constants. It turns out that the predicted variations are close to the present observational limits. Furthermore, we find that the time evolution of the dark matter particle masses should be crucially involved in the total mass variation of our Universe. A positive measurement of this kind of effects could be interpreted as strong support to the ''micro-macro connection'' (viz. the dynamical feedback between the evolution of the cosmological parameters and the time variation of the fundamental constants of the microscopic world), previously proposed by two of us (HF and JS). (orig.)
Selected hydraulic test analysis techniques for constant-rate discharge tests
International Nuclear Information System (INIS)
Spane, F.A. Jr.
1993-03-01
The constant-rate discharge test is the principal field method used in hydrogeologic investigations for characterizing the hydraulic properties of aquifers. To implement this test, the aquifer is stressed by withdrawing ground water from a well, by using a downhole pump. Discharge during the withdrawal period is regulated and maintained at a constant rate. Water-level response within the well is monitored during the active pumping phase (i.e., drawdown) and during the subsequent recovery phase following termination of pumping. The analysis of drawdown and recovery response within the stress well (and any monitored, nearby observation wells) provides a means for estimating the hydraulic properties of the tested aquifer, as well as discerning formational and nonformational flow conditions (e.g., wellbore storage, wellbore damage, presence of boundaries, etc.). Standard analytical methods that are used for constant-rate pumping tests include both log-log type-curve matching and semi-log straight-line methods. This report presents a current ''state of the art'' review of selected transient analysis procedures for constant-rate discharge tests. Specific topics examined include: analytical methods for constant-rate discharge tests conducted within confined and unconfined aquifers; effects of various nonideal formation factors (e.g., anisotropy, hydrologic boundaries) and well construction conditions (e.g., partial penetration, wellbore storage) on constant-rate test response; and the use of pressure derivatives in diagnostic analysis for the identification of specific formation, well construction, and boundary conditions
A study of group constant generation method in fast reactor analysis
International Nuclear Information System (INIS)
Takano, Hideki
1983-05-01
The methods of generating group constants have been studied to predict accurately the nuclear characteristics of fast reactors. In resonance energy region, the accuracy of the group constants was investigated, which were calculated by the approximate weighting spectrum used for a conventional standards group constant set such as ABBN. It was shown that the basic assumption of constant collision density for group constant calculation was not always satisfactory. Moreover, a multilevel formula was derived without losing the useful characteristics of the Breit-Wigner single level formula. Using this formula, the interference effect between resonances was examined. In addition, the mutual interference between different resonant nuclides was calculated. The cause of a systematic dependence of effective multiplication factors on U-238 concentration ratio was studied, and the cross section adjustment was performed. In the unresolved resonance region, the average resonance parameters were searched. As a result, the JFS-2 set was generated, and several studies were performed to advance the concept of the group constant set JFS-2. (Kako, I.)
Influx of CO2 from Soil Incubated Organic Residues at Constant Temperature
Directory of Open Access Journals (Sweden)
Shoukat Ali Abro
2016-06-01
Full Text Available Temperature induced CO2 from genotypic residue substances is still less understood. Two types of organic residues (wheat- maize were incubated at a constant temperature (25°C to determine the rate and cumulative influx of CO2 in laboratory experiment for 40 days. Further, the effect of surface and incorporated crop residues with and without phosphorus addition was also studied. Results revealed that mixing of crop residues increased CO2-C evolution significantly & emission rare was 37% higher than that of control. At constant temperature, soil mixed residues, had higher emission rates CO2-C than the residues superimposed. There was linear correlation of CO2-C influxed for phosphorus levels and residue application ways with entire incubation at constant temperature. The mixing of organic residues to soil enhanced SOC levels and biomass of microbially bound N; however to little degree ammonium (NH4-N and nitrate NO3-N nitrogen were decreased.
Measurement of Cardiac Output by Constant Injection of Radioactive Xenon
Energy Technology Data Exchange (ETDEWEB)
Kishon, Y.; Avasthey, P.; Barnett, A.; Shillingford, J. P. [MRC Cardiovascular Research Unit and Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London (United Kingdom)
1971-02-15
The method of determining cardiac output by the injection of {sup 133}Xe solution has been initially tested in a suitable hydrodynamic model, simulating the cardiovascular system. The indicator was infused in a constant rate into a ''pre-ventricular'' site through a fine polyethylene tubing, and samples were taken from a ''post-ventricular'' site through similar tubing. Specific activity was determined with the use of a universal well-type scintillation counter and output values were derived from the dilutional factor of the specific activity and the rate of the infusion. Good correlation with direct output measurements were demonstrated over a wide range of outputs, stroke volumes and end-diastolic volumes. The method remained valid when either the ''pre-ventricular'' or the ''post-ventricular'' valve was made incompetent. The method was then evaluated in anaesthetized dogs and cardiac output determinations were compared with those obtained by the Fick and dye-dilution techniques. The indicator was injected into the right atrium, and samples were obtained from the pulmonary artery through similar tubings. The method was found to be reliable over a wide range of cardiac outputs (drugs- and bleeding-induced) and in the presence of severe tricuspid incompetence (performed by a valvotome). Finally, the technique was used in six patients, both at rest and after exercise, and the cardiac output values were compared with those obtained by the Fick and the photoelectric-earpiece dye-dilution techniques. It is concluded that, provided the appropriate speed of injection (about 1.5 - 3.5 {mu}Ci/sec) and the time of sampling is carefully observed, good correlation between the method under investigation and other conventional methods could be shown. This method is more convenient for repeated determinations, simpler to perform and final values are obtained almost immediately. (author)
A reassessment of the presumed Neandertal remains from San Bernardino Cave, Italy.
Benazzi, Stefano; Peresani, Marco; Talamo, Sahra; Fu, Qiaomei; Mannino, Marcello A; Richards, Michael P; Hublin, Jean-Jacques
2014-01-01
In 1986-1987, three human remains were unearthed from macro-unit II of San Bernardino Cave (Berici Hills, Veneto, Italy), a deposit containing a late Mousterian lithic assemblage. The human remains (a distal phalanx, a lower right third molar and a lower right second deciduous incisor) do not show diagnostic morphological features that could be used to determine whether they were from Homo neanderthalensis or Homo sapiens. Despite being of small size, and thus more similar to recent H. sapiens, the specimens were attributed to Neandertals, primarily because they were found in Mousterian layers. We carried out a taxonomic reassessment of the lower right third molar (LRM3; San Bernardino 4) using digital morphometric analysis of the root, ancient DNA analysis, carbon and nitrogen isotope analyses, and direct accelerator mass spectrometry (AMS) radiocarbon dating of dentine collagen. Mitochondrial DNA analysis and root morphology show that the molar belongs to a modern human and not to a Neandertal. Carbon 14 ((14)C) dating of the molar attributes it to the end of the Middle Ages (1420-1480 cal AD, 2 sigma). Carbon and nitrogen isotope analyses suggest that the individual in question had a diet similar to that of Medieval Italians. These results show that the molar, as well as the other two human remains, belong to recent H. sapiens and were introduced in the Mousterian levels post-depositionally. Copyright © 2013 Elsevier Ltd. All rights reserved.
The use of fish remains in sediments for the reconstruction of paleoproductivity
Energy Technology Data Exchange (ETDEWEB)
Drago, T; Santos, A M P; Pinheiro, J [Institute Nacional de Recursos Biologicos (INRB), L-IPIMAR, Av. 5 de Outubro s/n 8700-305 OLHaO (Portugal); Ferreira-Bartrina, V [Centra de Investigacion CientIfica y de Educacion Superior de Ensenada- CICESE, Km. 107 Carretera Tijuana, C.P.22860, Ensenada, B.C. (Mexico)], E-mail: tdrago@ipimar.pt
2009-01-01
The majority of the works concerning fish productivity are based in fish landing records. However, in order to understand the causes of variability in fish productivity (natural and/or anthropogenic) it is essential to have information from periods when human impacts (e.g., fisheries) are considered unimportant. This can be achieved through the use of fish remains, i.e. scales, vertebrae and otoliths, from sediment records. The obtained data can be used to develop time series of fish stocks revealing the history of fish population dynamics over the last centuries or millennia. The majority of these works are located in Eastern Boundary Current Systems (e.g., Benguela, Peru-Humboldt, California), because these are associated with coastal upwelling and high productivity, which in some cases is at the origin of low bottom oxygen levels, leading to scale preservation. A search for fish remains in the Portuguese margin sediments is in progress in the context of the ongoing research project POPEI (High-resolution oceanic paleoproductivity and environmental changes; correlation with fish populations), which intend to fill the gap in studies of this type for the Canary Current System. In this paper we review some general ideas of the use of fish remains, related studies, methodologies and data processing, as well as presenting the first results of POPEI.
DEFF Research Database (Denmark)
Álvarez-Asencio, R.; Thormann, Esben; Rutland, M.W.
2013-01-01
A technique has been developed for the calculation of torsional spring constants for AFM cantilevers based on the combination of the normal spring constant and plate/beam theory. It is easy to apply and allow the determination of torsional constants for stiff cantilevers where the thermal power s...... spectrum is difficult to obtain due to the high resonance frequency and low signal/noise ratio. The applicability is shown to be general and this simple approach can thus be used to obtain torsional constants for any beam shaped cantilever. © 2013 AIP Publishing LLC....
Using Constant Time Delay to Teach Braille Word Recognition
Hooper, Jonathan; Ivy, Sarah; Hatton, Deborah
2014-01-01
Introduction: Constant time delay has been identified as an evidence-based practice to teach print sight words and picture recognition (Browder, Ahlbrim-Delzell, Spooner, Mims, & Baker, 2009). For the study presented here, we tested the effectiveness of constant time delay to teach new braille words. Methods: A single-subject multiple baseline…
Constant Cremer, voetballer in Tilburg met Afrikaanse wortels
Drs. Thijs Kemmeren
2012-01-01
Constant Cremer is de eerste zwarte voetballer in Nederland. Hij is geboren in Belgisch Congo. Hij speelde bij Willem II in het seizoen 1904 -1905 en werd met Willem II Brabvants kampioen. Constant werd, als een donkere mulat een held in Tilburg. Hij kwam uiteindelijk terecht in Nederland Indie en
Pricing constant maturity credit default swaps under jumo dynamics
Jönsson, H.; Schoutens, W.
2009-01-01
In this paper we discuss the pricing of Constant Maturity Credit Default Swaps (CMCDS) under single sided jump models. The CMCDS offers default protection in exchange for a floating premium which is periodically reset and indexed to the market spread on a CDS with constant maturity tenor written on
Lattice constant measurement from electron backscatter diffraction patterns
DEFF Research Database (Denmark)
Saowadee, Nath; Agersted, Karsten; Bowen, Jacob R.
2017-01-01
Kikuchi bands in election backscattered diffraction patterns (EBSP) contain information about lattice constants of crystallographic samples that can be extracted via the Bragg equation. An advantage of lattice constant measurement from EBSPs over diffraction (XRD) is the ability to perform local ...
Cosmological constant--the weight of the vacuum
International Nuclear Information System (INIS)
Padmanabhan, T.
2003-01-01
Recent cosmological observations suggest the existence of a positive cosmological constant Λ with the magnitude Λ(Gℎ/c 3 )∼10 -123 . This review discusses several aspects of the cosmological constant both from the cosmological (Sections 1-6) and field theoretical (Sections 7-11) perspectives. After a brief introduction to the key issues related to cosmological constant and a historical overview, a summary of the kinematics and dynamics of the standard Friedmann model of the universe is provided. The observational evidence for cosmological constant, especially from the supernova results, and the constraints from the age of the universe, structure formation, Cosmic Microwave Background Radiation (CMBR) anisotropies and a few others are described in detail, followed by a discussion of the theoretical models (quintessence, tachyonic scalar field, ...) from different perspectives. The latter part of the review (Sections 7-11) concentrates on more conceptual and fundamental aspects of the cosmological constant like some alternative interpretations of the cosmological constant, relaxation mechanisms to reduce the cosmological constant to the currently observed value, the geometrical structure of the de Sitter spacetime, thermodynamics of the de Sitter universe and the role of string theory in the cosmological constant problem
Coupler tuning for constant gradient travelling wave accelerating structures
International Nuclear Information System (INIS)
Guo Xingkun; Ma Yanyun; Wang Xiulong
2013-01-01
The method of the coupler tuning for the constant gradient traveling wave accelerating structure was described and the formula of coupling coefficient p was deduced on the basis of analyzing the existing methods for the constant impedance traveling wave accelerating structures and coupling-cavity chain equivalent circuits. The method and formula were validated by the simulation result by CST and experiment data. (authors)
Coupling constants (Tdn) and (Td*n) for local potentials
International Nuclear Information System (INIS)
Belyaev, V.B.; Irgaziev, B.F.; Orlov, Yu.V.
1976-01-01
The coupling constants (Tdn) and (Td*n) are found solving the Faddeev equations with local potentials. It is shown that the polinomial extrapolation of the wave function to the nonphysical region of the variable Q 2 turns not to be sure for determination of the coupling constants
Vector and axial constants of the baryon decuplet
International Nuclear Information System (INIS)
Belyaev, V.M.; Blok, B.Y.; Kogan, Y.I.
1985-01-01
On the basis of the QCD sum rules for the polarization operator in external axial and vector fields we determine the vector and axial transition constants in the 3/2 + baryon decuplet. We show that the renormalization of the axial constant is due to the interaction of the external axial field with the quark condensate
Measuring Boltzmann's Constant with Carbon Dioxide
Ivanov, Dragia; Nikolov, Stefan
2013-01-01
In this paper we present two experiments to measure Boltzmann's constant--one of the fundamental constants of modern-day physics, which lies at the base of statistical mechanics and thermodynamics. The experiments use very basic theory, simple equipment and cheap and safe materials yet provide very precise results. They are very easy and…
Elastic constants of diamond from molecular dynamics simulations
International Nuclear Information System (INIS)
Gao Guangtu; Van Workum, Kevin; Schall, J David; Harrison, Judith A
2006-01-01
The elastic constants of diamond between 100 and 1100 K have been calculated for the first time using molecular dynamics and the second-generation, reactive empirical bond-order potential (REBO). This version of the REBO potential was used because it was redesigned to be able to model the elastic properties of diamond and graphite at 0 K while maintaining its original capabilities. The independent elastic constants of diamond, C 11 , C 12 , and C 44 , and the bulk modulus were all calculated as a function of temperature, and the results from the three different methods are in excellent agreement. By extrapolating the elastic constant data to 0 K, it is clear that the values obtained here agree with the previously calculated 0 K elastic constants. Because the second-generation REBO potential was fit to obtain better solid-state force constants for diamond and graphite, the agreement with the 0 K elastic constants is not surprising. In addition, the functional form of the second-generation REBO potential is able to qualitatively model the functional dependence of the elastic constants and bulk modulus of diamond at non-zero temperatures. In contrast, reactive potentials based on other functional forms do not reproduce the correct temperature dependence of the elastic constants. The second-generation REBO potential also correctly predicts that diamond has a negative Cauchy pressure in the temperature range examined
Theory of the change of elastic constants by interstitials
International Nuclear Information System (INIS)
Breuer, N.; Dederichs, P.H.; Lehmann, C.; Leibfried, G.; Scholz, A.
1975-01-01
The theory of the change of elastic constants by point-defects, in particular by interstitials, is briefly summarized. The typical effects of spring changes in a defect lattice on the elastic data are discussed qualitatively. Numerical results for the change of elastic constants by self-interstitials and vacancies are given and compared with experimental data for Cu and Al
Constant Width Planar Computation Characterizes ACC^{0}
DEFF Research Database (Denmark)
Hansen, K.A.
2004-01-01
We obtain a characterization of ACC 0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...
International Nuclear Information System (INIS)
Mohamadou, Youssoufa; Oh, Tong In; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee
2012-01-01
Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (R s ) and an external sample. To maintain high SNR, R s is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz
Time variable cosmological constants from the age of universe
International Nuclear Information System (INIS)
Xu Lixin; Lu Jianbo; Li Wenbo
2010-01-01
In this Letter, time variable cosmological constant, dubbed age cosmological constant, is investigated motivated by the fact: any cosmological length scale and time scale can introduce a cosmological constant or vacuum energy density into Einstein's theory. The age cosmological constant takes the form ρ Λ =3c 2 M P 2 /t Λ 2 , where t Λ is the age or conformal age of our universe. The effective equation of state (EoS) of age cosmological constant are w Λ eff =-1+2/3 (√(Ω Λ ))/c and w Λ eff =-1+2/3 (√(Ω Λ ))/c (1+z) when the age and conformal age of universe are taken as the role of cosmological time scales respectively. The EoS are the same as the so-called agegraphic dark energy models. However, the evolution histories are different from the agegraphic ones for their different evolution equations.
Fundamental Constants in Physics and their Time Dependence
CERN. Geneva
2008-01-01
In the Standard Model of Particle Physics we are dealing with 28 fundamental constants. In the experiments these constants can be measured, but theoretically they are not understood. I will discuss these constants, which are mostly mass parameters. Astrophysical measurements indicate that the finestructure constant is not a real constant, but depends on time. Grand unification then implies also a time variation of the QCD scale. Thus the masses of the atomic nuclei and the magnetic moments of the nuclei will depend on time. I proposed an experiment, which is currently done by Prof. Haensch in Munich and his group. The first results indicate a time dependence of the QCD scale. I will discuss the theoretical implications.
Transport equivalent diffusion constants for reflector region in PWRs
International Nuclear Information System (INIS)
Tahara, Yoshihisa; Sekimoto, Hiroshi
2002-01-01
The diffusion-theory-based nodal method is widely used in PWR core designs for reason of its high computing speed in three-dimensional calculations. The baffle/reflector (B/R) constants used in nodal calculations are usually calculated based on a one-dimensional transport calculation. However, to achieve high accuracy of assembly power prediction, two-dimensional model is needed. For this reason, the method for calculating transport equivalent diffusion constants of reflector material was developed so that the neutron currents on the material boundaries could be calculated exactly in diffusion calculations. Two-dimensional B/R constants were calculated using the transport equivalent diffusion constants in the two-dimensional diffusion calculation whose geometry reflected the actual material configuration in the reflector region. The two-dimensional B/R constants enabled us to predict assembly power within an error of 1.5% at hot full power conditions. (author)
DEFF Research Database (Denmark)
Faber, Rasmus; Sauer, Stephan P. A.
2015-01-01
We present zero-point vibrational corrections to the indirect nuclear spin-spin coupling constants in ethyne, ethene, cyclopropene and allene. The calculations have been carried out both at the level of the second order polarization propagator approximation (SOPPA) employing a new implementation ...
Bethlem, H.L.; Ubachs, W.M.G.
2009-01-01
The recently demonstrated methods to cool and manipulate neutral molecules offer new possibilities for precision tests of fundamental physics theories. We here discuss the possibility of testing the time-invariance of fundamental constants using near degeneracies between rotational levels in the
The CRC 20 years: An overview of some of the major achievements and remaining challenges.
Doek, Jaap E
2009-11-01
On 20 November 1989, the General Assembly of the United Nations adopted the Convention on the Rights of the Child (CRC). It entered into force on 2 September 1990 and has by now been ratified by 193 States, making the most universally ratified human rights treaty. This overview will present and discuss the impact of this treaty both at the international and the national level, an overview which necessarily has to be limited to some of the developments as a result of the implementation of the CRC. The first part of this paper will be devoted to the impact the CRC had and still has on the setting and development of the international agenda for the promotion and protection of the rights and welfare of children. Special attention will given to developments, achievements, and remaining challenges at the international level with regard to protection of children in armed conflict; prevention and the protection of children from sexual exploitation; and from all forms of violence. This will include some information on the impact of these international developments and actions at the national level, for example, in the area of legislation. The second part will focus on the impact at the national level. Given the wide scope of the CRC this part will be limited to some of the General Measures of Implementation (law reform, national programmes, and independent monitoring) and the General Principles (non-discrimination, best interest, right to be heard) of the CRC. This will be based on reports of States on the implementation of the CRC submitted to the CRC Committee and the Concluding Observations of this Committee and on a number of studies. The conclusion will provide remarks on poverty as one of the major remaining challenges for the implementation of children's rights.
Theory of superconductivity. II. Excited Cooper pairs. Why does sodium remain normal down to 0 K?
International Nuclear Information System (INIS)
Fujita, S.
1992-01-01
Based on a generalized BCS Hamiltonian in which the interaction strengths (V 11 , V 22 , V 12 ) among and between electron (12) and hole (2) Cooper pairs are differentiated, the thermodynamic properties of a type-I superconductor below the critical temperature T c are investigated. An expression for the ground-state energy, W - W 0 , relative to the unperturbed Block system is obtained. The usual BCS formulas are obtained in the limits: (all) V jl = V 0 , N 1 (0) = N 2 (0). Any excitations generated through the BCS interaction Hamiltonian containing V jl must involve Cooper pairs of antiparallel spins and nearly opposite momenta. The nonzero momentum or excited Cooper pairs below T c are shown to have an excitation energy band minimum lower than the quasi-electrons, which were regarded as the elementary excitations in the original BCS theory. The energy gap var-epsilon g (T) defined relative to excited and zero-momentum Copper pairs (when V jl > 0) decreases from var-epsilon g (0) to 0 as the temperature T is raised from 0 to T c . If electrons only are available as in a monovalent metal like sodium (V 12 = 0), the energy constant Δ 1 is finite but the energy gap vanishes identically for all T. In agreement with the BCS theory, the present theory predicts that a pure nonmagnetic metal in any dimensions should have a Cooper-pair ground state whose energy is lower than that of the Bloch ground state. Additionally it predicts that a monovalent metal should remain normal down to 0 K, and that there should be no strictly one-dimensional superconductor
International Nuclear Information System (INIS)
Zhang, Yulian; Cheng, Weijie; Du, Fei; Zhang, Shaoyu; Ma, Weihua; Li, Dongdong; Song, Ye; Zhu, Xufei
2015-01-01
Highlights: • Ti anodization was performed by constant current rather than constant voltage. • The nanotube length was controlled by ionic current rather than dissolution current. • Electronic current can be estimated by the nanotube length and the anodizing current. • Dissolution reaction hardly contributes electric current across the barrier layer. - Abstract: The growth kinetics of anodic TiO 2 nanotubes (ATNTs) still remains unclear. ATNTs are generally fabricated under potentiostatic conditions rather than galvanostatic ones. The quantitative relationship between nanotube length and anodizing current (J total ) is difficult to determine, because the variable J total includes ionic current (J ion ) (also called oxide growth current J grow =J ion ) and electronic current (J e ), which cannot be separated from each other. One successful approach to achieve this objective is to use constant current anodization rather than constant voltage anodization, that is, through quantitative comparison between the nanotube length and the known J total during constant current anodization, we can estimate the relative magnitudes of J grow and J e . The nanotubes with lengths of 1.24, 2.23, 3.51 and 4.70 μm, were formed under constant currents (J total ) of 15, 20, 25 and 30 mA, respectively. The relationship between nanotube length (y) and anodizing current (x =J total =J grow +J e ) can be expressed by a fitting equation: y=0.23(x-10.13), from which J grow (J grow = x -10.13) and J e (∼10.13 mA) could be inferred under the present conditions. Meanwhile, the same conclusion could also be deduced from the oxide volume data. These results indicate that the nanotube growth is attributed to the oxide growth current rather than the dissolution current.
Macroscopic multigroup constants for accelerator driven system core calculation
International Nuclear Information System (INIS)
Heimlich, Adino; Santos, Rubens Souza dos
2011-01-01
The high-level wastes stored in facilities above ground or shallow repositories, in close connection with its nuclear power plant, can take almost 106 years before the radiotoxicity became of the order of the background. While the disposal issue is not urgent from a technical viewpoint, it is recognized that extended storage in the facilities is not acceptable since these ones cannot provide sufficient isolation in the long term and neither is it ethical to leave the waste problem to future generations. A technique to diminish this time is to transmute these long-lived elements into short-lived elements. The approach is to use an Accelerator Driven System (ADS), a sub-critical arrangement which uses a Spallation Neutron Source (SNS), after separation the minor actinides and the long-lived fission products (LLFP), to convert them to short-lived isotopes. As an advanced reactor fuel, still today, there is a few data around these type of core systems. In this paper we generate macroscopic multigroup constants for use in calculations of a typical ADS fuel, take into consideration, the ENDF/BVI data file. Four energy groups are chosen to collapse the data from ENDF/B-VI data file by PREPRO code. A typical MOX fuel cell is used to validate the methodology. The results are used to calculate one typical subcritical ADS core. (author)
Renormalization constants for 2-twist operators in twisted mass QCD
International Nuclear Information System (INIS)
Alexandrou, C.; Constantinou, M.; Panagopoulos, H.; Stylianou, F.; Korzec, T.
2011-01-01
Perturbative and nonperturbative results on the renormalization constants of the fermion field and the twist-2 fermion bilinears are presented with emphasis on the nonperturbative evaluation of the one-derivative twist-2 vector and axial-vector operators. Nonperturbative results are obtained using the twisted mass Wilson fermion formulation employing two degenerate dynamical quarks and the tree-level Symanzik improved gluon action. The simulations have been performed for pion masses in the range of about 450-260 MeV and at three values of the lattice spacing a corresponding to β=3.9, 4.05, 4.20. Subtraction of O(a 2 ) terms is carried out by performing the perturbative evaluation of these operators at 1-loop and up to O(a 2 ). The renormalization conditions are defined in the RI ' -MOM scheme, for both perturbative and nonperturbative results. The renormalization factors, obtained for different values of the renormalization scale, are evolved perturbatively to a reference scale set by the inverse of the lattice spacing. In addition, they are translated to MS at 2 GeV using 3-loop perturbative results for the conversion factors.
Evidence against solar influence on nuclear decay constants
Directory of Open Access Journals (Sweden)
S. Pommé
2016-10-01
Full Text Available The hypothesis that proximity to the Sun causes variation of decay constants at permille level has been tested and disproved. Repeated activity measurements of mono-radionuclide sources were performed over periods from 200 days up to four decades at 14 laboratories across the globe. Residuals from the exponential nuclear decay curves were inspected for annual oscillations. Systematic deviations from a purely exponential decay curve differ from one data set to another and are attributable to instabilities in the instrumentation and measurement conditions. The most stable activity measurements of alpha, beta-minus, electron capture, and beta-plus decaying sources set an upper limit of 0.0006% to 0.008% to the amplitude of annual oscillations in the decay rate. Oscillations in phase with Earth's orbital distance to the Sun could not be observed within a 10−6 to 10−5 range of precision. There are also no apparent modulations over periods of weeks or months. Consequently, there is no indication of a natural impediment against sub-permille accuracy in half-life determinations, renormalisation of activity to a distant reference date, application of nuclear dating for archaeology, geo- and cosmochronology, nor in establishing the SI unit becquerel and seeking international equivalence of activity standards.
2011-03-15
...: University of Wyoming, Anthropology Department, Human Remains Repository, Laramie, WY AGENCY: National Park... in the possession and control of the University of Wyoming Anthropology Department, Human Remains... made by University of Wyoming, Anthropology Department, Human Remains Repository, professional staff in...
International Nuclear Information System (INIS)
1989-01-01
The dissociation constants of the weak acids derived from quinizarin (1,4-dihydroxy anthraquinone); QMF (2-(2-fury l methyl)), QMPH (2-(2-phenyl methyl)) and QMN (2-(2-naphthyl methyl)) quinizarin were determined. The stability constants of uranyl complexes with the above mentioned ligands were investigated by: 1. The molar-ratio method. 2. Computer program
ℋ∞ constant gain state feedback stabilization of stochastic hybrid systems with Wiener process
Directory of Open Access Journals (Sweden)
E. K. Boukas
2004-01-01
Full Text Available This paper considers the stabilization problem of the class of continuous-time linear stochastic hybrid systems with Wiener process. The ℋ∞ state feedback stabilization problem is treated. A state feedback controller with constant gain that does not require access to the system mode is designed. LMI-based conditions are developed to design the state feedback controller with constant gain that stochastically stabilizes the studied class of systems and, at the same time, achieve the disturbance rejection of a desired level. The minimum disturbance rejection is also determined. Numerical examples are given to show the usefulness of the proposed results.
International Nuclear Information System (INIS)
Nagao, G.
1987-12-01
We recalculate the bosonic 1-loop open string scattering amplitude using the results of the bosonic 1-loop closed string amplitude. The results show explicitly how the cancellation of divergences depends upon of a set of involution-dependent constants which relate the torus to the cylinder and Moebius strip. Such a set of involution-dependent constants exists at each loop level and thus provides a means with which to study the cancellation of divergences and the connection between the world-sheet and internal symmetries. 14 refs., 3 figs
One-particle reducible contribution to the one-loop spinor propagator in a constant field
Directory of Open Access Journals (Sweden)
N. Ahmadiniaz
2017-11-01
Full Text Available Extending work by Gies and Karbstein on the Euler–Heisenberg Lagrangian, it has recently been shown that the one-loop propagator of a charged scalar particle in a constant electromagnetic field has a one-particle reducible contribution in addition to the well-studied irreducible one. Here we further generalize this result to the spinor case, and find the same relation between the reducible term, the tree-level propagator and the one-loop Euler–Heisenberg Lagrangian as in the scalar case. Our demonstration uses a novel worldline path integral representation of the photon-dressed spinor propagator in a constant electromagnetic field background.
Norepinephrine remains increased in the six-minute walking test after heart transplantation
Directory of Open Access Journals (Sweden)
Guilherme Veiga Guimarães
2010-01-01
Full Text Available OBJECTIVE: We sought to evaluate the neurohormonal activity in heart transplant recipients and compare it with that in heart failure patients and healthy subjects during rest and just after a 6-minute walking test. INTRODUCTION: Despite the improvements in quality of life and survival provided by heart transplantation, the neurohormonal profile is poorly described. METHODS: Twenty heart transplantation (18 men, 49±11 years and 8.5±3.3 years after transplantation, 11 heart failure (8 men, 43±10 years, and 7 healthy subjects (5 men 39±8 years were included in this study. Blood samples were collected immediately before and during the last minute of the exercise. RESULTS: During rest, patients' norepinephrine plasma level (659±225 pg/mL was higher in heart transplant recipients (463±167 pg/mL and heathy subjects (512±132, p<0.05. Heart transplant recipient's norepinephrine plasma level was not different than that of healthy subjects. Just after the 6-minute walking test, the heart transplant recipient's norepinephrine plasma level (1248±692 pg/mL was not different from that of heart failure patients (1174±653 pg/mL. Both these groups had a higher level than healthy subjects had (545±95 pg/mL, p<0.05. CONCLUSION: Neurohormonal activity remains increased after the 6-minute walking test after heart transplantation.
Ramirez de Noriega, Fernando; Eitan, Renana; Marmor, Odeya; Lavi, Adi; Linetzky, Eduard; Bergman, Hagai; Israel, Zvi
2015-02-18
Background: Subthalamic nucleus (STN) deep brain stimulation (DBS) is an established therapy for advanced Parkinson's disease (PD). Motor efficacy and safety have been established for constant voltage (CV) devices and more recently for constant current (CC) devices. CC devices adjust output voltage to provide CC stimulation irrespective of impedance fluctuation, while the current applied by CV stimulation depends on the impedance that may change over time. No study has directly compared the clinical effects of these two stimulation modalities. Objective: To compare the safety and clinical impact of CC STN DBS to CV STN DBS in patients with advanced PD 2 years after surgery. Methods: Patients were eligible for inclusion if they had undergone STN DBS surgery for idiopathic PD, had been implanted with a Medtronic Activa PC and if their stimulation program and medication had been stable for at least 1 year. This single-center trial was designed as a double-blind, randomized, prospective study with crossover after 2 weeks. Motor equivalence of the 2 modalities was confirmed utilizing part III of the Unified Parkinson's Disease Rating Scale (UPDRS). PD diaries and multiple subjective and objective evaluations of quality of life, depression, cognition and emotional processing were evaluated on both CV and on CC stimulation. Analysis using the paired t test with Bonferroni correction for multiple comparisons was performed to identify any significant difference between the stimulation modalities. Results: 8 patients were recruited (6 men, 2 women); 1 patient did not complete the study. The average age at surgery was 56.7 years (range 47-63). Disease duration at the time of surgery was 7.5 years (range 3-12). Patients were recruited 23.8 months (range 22.5-24) after surgery. At the postoperative study baseline, this patient group showed an average motor improvement of 69% (range 51-97) as measured by the change in UPDRS part III with stimulation alone. Levodopa equivalent
Charge dependence of the pion-nucleon coupling constant
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V. A. Babenko
2015-07-01
Full Text Available On the basis of the Yukawa potential we study the pion-nucleon coupling constants for the neutral and charged pions assuming that nuclear forces at low energies are mainly determined by the exchange of virtual pions. We obtain the charged pseudovector pion-nucleon coupling constant f2π± = 0.0804(7 by making the use of experimental low-energy scattering parameters for the singlet pp- and np-scattering, and also by use of the neutral pseudovector pion-nucleon coupling constant f2π0 = 0.0749(7. Corresponding value of the charged pseudoscalar pion-nucleon coupling constant g2π0 / 4π = 14.55(13 is also determined. This calculated value of the charged pseudoscalar pion-nucleon coupling constant is in fully agreement with the experimental constant g2π0 / 4π = 14.52(26 obtained by the Uppsala Neutron Research Group. Our results show considerable charge splitting of the pion-nucleon coupling constant.
Larson-Miller Constant of Heat-Resistant Steel
Tamura, Manabu; Abe, Fujio; Shiba, Kiyoyuki; Sakasegawa, Hideo; Tanigawa, Hiroyasu
2013-06-01
Long-term rupture data for 79 types of heat-resistant steels including carbon steel, low-alloy steel, high-alloy steel, austenitic stainless steel, and superalloy were analyzed, and a constant for the Larson-Miller (LM) parameter was obtained in the current study for each material. The calculated LM constant, C, is approximately 20 for heat-resistant steels and alloys except for high-alloy martensitic steels with high creep resistance, for which C ≈ 30 . The apparent activation energy was also calculated, and the LM constant was found to be proportional to the apparent activation energy with a high correlation coefficient, which suggests that the LM constant is a material constant possessing intrinsic physical meaning. The contribution of the entropy change to the LM constant is not small, especially for several martensitic steels with large values of C. Deformation of such martensitic steels should accompany a large entropy change of 10 times the gas constant at least, besides the entropy change due to self-diffusion.