Molecular mechanism of direct proflavine-DNA intercalation: evidence for drug-induced minimum base-stacking penalty pathway.

PubMed

Sasikala, Wilbee D; Mukherjee, Arnab

2012-10-11

DNA intercalation, a biophysical process of enormous clinical significance, has surprisingly eluded molecular understanding for several decades. With appropriate configurational restraint (to prevent dissociation) in all-atom metadynamics simulations, we capture the free energy surface of direct intercalation from minor groove-bound state for the first time using an anticancer agent proflavine. Mechanism along the minimum free energy path reveals that intercalation happens through a minimum base stacking penalty pathway where nonstacking parameters (Twist→Slide/Shift) change first, followed by base stacking parameters (Buckle/Roll→Rise). This mechanism defies the natural fluctuation hypothesis and provides molecular evidence for the drug-induced cavity formation hypothesis. The thermodynamic origin of the barrier is found to be a combination of entropy and desolvation energy.

Minimum distribution of subsea ice-bearing permafrost on the US Beaufort Sea continental shelf

USGS Publications Warehouse

Brothers, Laura L.; Hart, Patrick E.; Ruppel, Carolyn D.

2012-01-01

Starting in Late Pleistocene time (~19 ka), sea level rise inundated coastal zones worldwide. On some parts of the present-day circum-Arctic continental shelf, this led to flooding and thawing of formerly subaerial permafrost and probable dissociation of associated gas hydrates. Relict permafrost has never been systematically mapped along the 700-km-long U.S. Beaufort Sea continental shelf and is often assumed to extend to ~120 m water depth, the approximate amount of sea level rise since the Late Pleistocene. Here, 5,000 km of multichannel seismic (MCS) data acquired between 1977 and 1992 were examined for high-velocity (>2.3 km s−1) refractions consistent with ice-bearing, coarse-grained sediments. Permafrost refractions were identified along <5% of the tracklines at depths of ~5 to 470 m below the seafloor. The resulting map reveals the minimum extent of subsea ice-bearing permafrost, which does not extend seaward of 30 km offshore or beyond the 20 m isobath.

X-ray Monitoring of eta Carinae: Variations on a Theme

NASA Technical Reports Server (NTRS)

Corcoran, M. F.

2004-01-01

We present monitoring observations by the Rossi X-ray Timing Explorer of the 2-10 keV X-ray emission from the supermassive star eta Carinae from 1996 through late 2003. These data cover more than one of the stellar variability cycles in temporal detail and include especially detailed monitoring through two X-ray minima. We compare the current X-ray minimum which began on June 29, 2003 to the previous X-ray minimum which began on December 15, 1997, and refine the X-ray period to 2024 days. We examine the variations in the X-ray spectrum with phase and with time, and also refine our understanding of the X-ray peaks which have a quasi-period of 84 days, with significant variation. Cycle-to-cycle differences are seen in the level of X-ray intensity and in the detailed variations of the X-ray flux on the rise to maximum just prior to the X-ray minimum. Despite these differences the similarities between the decline to minimum, the duration of the minimum, and correlated variations of the X-ray flux and other measures throughout the electromagnetic spectrum leave little doubt that that the X-ray variation is strictly periodic and produced by orbital motion as the wind from eta Carinae collides with the wind of an otherwise unseen companion.

Modeling and control for a magnetic levitation system based on SIMLAB platform in real time

NASA Astrophysics Data System (ADS)

Yaseen, Mundher H. A.; Abd, Haider J.

2018-03-01

Magnetic Levitation system becomes a hot topic of study due to the minimum friction and low energy consumption which regards as very important issues. This paper proposed a new magnetic levitation system using real-time control simulink feature of (SIMLAB) microcontroller. The control system of the maglev transportation system is verified by simulations with experimental results, and its superiority is indicated in comparison with previous literature and conventional control strategies. In addition, the proposed system was implemented under effect of three controller types which are Linear-quadratic regulator (LQR), proportional-integral-derivative controller (PID) and Lead compensation. As well, the controller system performance was compared in term of three parameters Peak overshoot, Settling time and Rise time. The findings prove the agreement of simulation with experimental results obtained. Moreover, the LQR controller produced a great stability and homogeneous response than other controllers used. For experimental results, the LQR brought a 14.6%, 0.199 and 0.064 for peak overshoot, Setting time and Rise time respectively.

Long-term trends in daily temperature extremes in Iraq

NASA Astrophysics Data System (ADS)

Salman, Saleem A.; Shahid, Shamsuddin; Ismail, Tarmizi; Chung, Eun-Sung; Al-Abadi, Alaa M.

2017-12-01

The existence of long-term persistence (LTP) in hydro-climatic time series can lead to considerable change in significance of trends. Therefore, past findings of climatic trend studies that did not consider LTP became a disputable issue. A study has been conducted to assess the trends in temperature and temperature extremes in Iraq in recent years (1965-2015) using both ordinary Mann-Kendal (MK) test; and the modified Mann-Kendall (m-MK) test, which can differentiate the multi-decadal oscillatory variations from secular trends. Trends in annual and seasonal minimum and maximum temperatures, diurnal temperature range (DTR), and 14 temperature-related extremes were assessed. MK test detected the significant increases in minimum and maximum temperature at all stations, where m-MK test detected at 86% and 80% of all stations, respectively. The temperature in Iraq is increasing 2 to 7 times faster than global temperature rise. The minimum temperature is increasing more (0.48-1.17 °C/decade) than maximum temperature (0.25-1.01 °C/decade). Temperature rise is higher in northern Iraq and in summer. The hot extremes particularly warm nights are increasing all over Iraq at a rate of 2.92-10.69 days/decade, respectively. On the other hand, numbers of cold days are decreasing at some stations at a rate of - 2.65 to - 8.40 days/decade. The use of m-MK test along with MK test confirms the significant increase in temperature and some of the temperature extremes in Iraq. This study suggests that trends in many temperature extremes in the region estimated in previous studies using MK test may be due to natural variability of climate, which empathizes the need for validation of the trends by considering LTP in time series.

On the Relation Between Spotless Days and the Sunspot Cycle

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2005-01-01

Spotless days are examined as a predictor for the size and timing of a sunspot cycle. For cycles 16-23 the first spotless day for a new cycle, which occurs during the decline of the old cycle, is found to precede minimum amplitude for the new cycle by about approximately equal to 34 mo, having a range of 25-40 mo. Reports indicate that the first spotless day for cycle 24 occurred in January 2004, suggesting that minimum amplitude for cycle 24 should be expected before April 2007, probably sometime during the latter half of 2006. If true, then cycle 23 will be classified as a cycle of shorter period, inferring further that cycle 24 likely will be a cycle of larger than average minimum and maximum amplitudes and faster than average rise, peaking sometime in 2010.

Tachyon field non-minimally coupled to massive neutrino matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmad, Safia; Myrzakulov, Nurgissa; Myrzakulov, R., E-mail: safia@ctp-jamia.res.in, E-mail: nmyrzakulov@gmail.com, E-mail: rmyrzakulov@gmail.com

2016-07-01

In this paper, we consider rolling tachyon, with steep run-away type of potentials non-minimally coupled to massive neutrino matter. The coupling dynamically builds up at late times as neutrino matter turns non-relativistic. In case of scaling and string inspired potentials, we have shown that non-minimal coupling leads to minimum in the field potential. Given a suitable choice of model parameters, it is shown to give rise to late-time acceleration with the desired equation of state.

An Estimate of the Size and Shape of Sunspot Cycle 24 Based on its Early Cycle Behavior using the Hathaway-Wilson-Reichmann Shape-Fitting Function

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2011-01-01

On the basis of 12-month moving averages (12-mma) of monthly mean sunspot number (R), sunspot cycle 24 had its minimum amplitude (Rm = 1.7) in December 2008. At 12 mo past minimum, R measured 8.3, and at 18 mo past minimum, it measured 16.4. Thus far, the maximum month-to-month rate of rise in 12-mma values of monthly mean sunspot number (AR(t) max) has been 1.7, having occurred at elapsed times past minimum amplitude (t) of 14 and 15 mo. Compared to other sunspot cycles of the modern era, cycle 24?s Rm and AR(t) max (as observed so far) are the smallest on record, suggesting that it likely will be a slow-rising, long-period sunspot cycle of below average maximum amplitude (RM). Supporting this view is the now observed relative strength of cycle 24?s geomagnetic minimum amplitude as measured using the 12-mma value of the aa-geomagnetic index (aam = 8.4), which also is the smallest on record, having occurred at t equals 8 and 9 mo. From the method of Ohl (the inferred preferential association between RM and aam), one predicts RM = 55 +/- 17 (the ?1 se prediction interval) for cycle 24. Furthermore, from the Waldmeier effect (the inferred preferential association between the ascent duration (ASC) and RM) one predicts an ASC longer than 48 mo for cycle 24; hence, maximum amplitude occurrence should be after December 2012. Application of the Hathaway-Wilson-Reichmann shape-fitting function, using an RM = 70 and ASC = 56 mo, is found to adequately fit the early sunspot number growth of cycle 24.

Frequency and time properties of decimeter narrowband spikes in solar flares

NASA Astrophysics Data System (ADS)

Wang, Shujuan

2013-07-01

In this paper, we focus to study the frequency and time properties of a group of spikes recorded by the 1.08-2.04 GHz spectrometer of NAOC on 27 October 2003. At the first we calculate the mean and minimum bandwidth of the spikes. We apply two different methods based on the wavelet analysis according to Messmer & Benz (2000). The first method determines the dominant spike bandwidth scale based on their scalegram, and the second method is a feature detection algorithm in the time-frequency plane. Secondly the time profile of each single spike was fitted and analyzed. In particular, we determined the e-folding rise and decay times corresponding to the ascending and decaying parts of the time profile, respectively. Several important correlations were studied and compared with the results in earlier literature, i.e. those between duration and frequency, e-folding rise time and decay time, e-folding decay time and duration, and e-folding decay time and peak flux. Finally some parameters of source region were estimated and the possible decaying mechanism was discussed.

[Culpability and the problem of the human genome. Between being and having to be].

PubMed

Donna, Edgardo

2011-01-01

In a liberal-democratic system, there is no possibility of a criminal liability charge without a minimum of freedom. Nevertheless, since a long time ago and, nowadays, with the advancement of science in the human genome, understanding it as a closed system--farm theory--is intended to demonstrate that the genome is a destination, thus criminal liability will be void, giving rise to security measures.

The effect of working gas pressure on the switching rate of a kivotron

NASA Astrophysics Data System (ADS)

Bokhan, P. A.; Gugin, P. P.; Zakrevsky, D. E.; Lavrukhin, M. A.

2016-05-01

The switching rate in gas-discharge devices (kivotrons) based on an "open" discharge with counterpropagating electron beams is studied experimentally. Structures with a total cathode area of 2 cm2 were used. A monotonic reduction in the switching time with an increase in the working gas pressure and in the voltage amplitude at the time of breakdown is demonstrated. The minimum switching time is ~240 ps at a voltage of 17 kV. The maximum current rise rate, which is limited by the discharge circuit inductance, is 3 × 1012 A/s.

Large Topographic Rises on Venus: Implications for Mantle Upwelling

NASA Technical Reports Server (NTRS)

Stofan, Ellen R.; Smrekar, Suzanne E.; Bindschandler, Duane L.; Senske, David A.

1995-01-01

Topographic rises on Venus have been identified that are interpreted to be the surface manifestation of mantle upwellings. These features are classified into groups based on their dominant morphology. Atla and Beta Regiones are classified as rift-dominated, Dione, western Eistla, Bell, and Imdr Regiones as volcano-dominated, and Themis, eastern Eistla, and central Eistla Regiones as corona-dominated. At several topographic rises, geologic indicators were identified that may provide evidence of uplifted topography (e.g., volcanic flow features trending upslope). We assessed the minimum contribution of volcanic construction to the topography of each rise, which in general represents less than 5% of the volume of the rise, similar to the volumes of edifices at terrestrial hotspot swells. The total melt volume at each rise is approximated to be 10(exp 4) - 10(exp 6) cu km. The variations in morphology, topography, and gravity signatures at topographic rises are not interpreted to indicate variations in stage of evolution of a mantle upwelling. Instead, the morphologic variations between the three classes of topographic rises are interpreted to indicate the varying influences of lithospheric structure, plume characteristics, and regional tectonic environment. Within each class, variations in topography, gravity, and amount of volcanism may be indicative of differing stages of evolution. The similarity between swell and volcanic volumes for terrestrial and Venusian hotspots implies comparable time-integrated plume strengths for individual upwellings on the two planets.

Future changes over the Himalayas: Maximum and minimum temperature

NASA Astrophysics Data System (ADS)

Dimri, A. P.; Kumar, D.; Choudhary, A.; Maharana, P.

2018-03-01

An assessment of the projection of minimum and maximum air temperature over the Indian Himalayan region (IHR) from the COordinated Regional Climate Downscaling EXperiment- South Asia (hereafter, CORDEX-SA) regional climate model (RCM) experiments have been carried out under two different Representative Concentration Pathway (RCP) scenarios. The major aim of this study is to assess the probable future changes in the minimum and maximum climatology and its long-term trend under different RCPs along with the elevation dependent warming over the IHR. A number of statistical analysis such as changes in mean climatology, long-term spatial trend and probability distribution function are carried out to detect the signals of changes in climate. The study also tries to quantify the uncertainties associated with different model experiments and their ensemble in space, time and for different seasons. The model experiments and their ensemble show prominent cold bias over Himalayas for present climate. However, statistically significant higher warming rate (0.23-0.52 °C/decade) for both minimum and maximum air temperature (Tmin and Tmax) is observed for all the seasons under both RCPs. The rate of warming intensifies with the increase in the radiative forcing under a range of greenhouse gas scenarios starting from RCP4.5 to RCP8.5. In addition to this, a wide range of spatial variability and disagreements in the magnitude of trend between different models describes the uncertainty associated with the model projections and scenarios. The projected rate of increase of Tmin may destabilize the snow formation at the higher altitudes in the northern and western parts of Himalayan region, while rising trend of Tmax over southern flank may effectively melt more snow cover. Such combined effect of rising trend of Tmin and Tmax may pose a potential threat to the glacial deposits. The overall trend of Diurnal temperature range (DTR) portrays increasing trend across entire area with highest magnitude under RCP8.5. This higher rate of increase is imparted from the predominant rise of Tmax as compared to Tmin.

Permian Minimum and the Following Major Rise in Seawater 87Sr/86Sr Linked to the Glaciation/Deglaciation and Resultant Change in Weathering Rate

NASA Astrophysics Data System (ADS)

Kani, T.; Isozaki, Y.

2014-12-01

We report a detailed secular change of the middle Middle to early Late Permian seawater 87Sr/86Sr ratio for and Akasaka and Kamura carbonates (Japan) deposited on mid-Pansalassan seamounts and for Shizipo carbonates (South China) deposited on the shallow marine shelf. In these coeval sections, extremely low values (<0.7069; the lowest values of the Phanerozoic) continued from upper Wordian (middle Middle Permian) to the topmost Capitanian (upper Middle Permian) barren interval immediately below the Middle-Late Permian boundary characterized by the major crisis of large-tested fusulines and rugose corals. Immediately after ca. 5 m.y.-long minimum interval, the major rise in 87Sr/86Sr was started and the rate of the rise (0.00007/m.y.) continued in period of time containing 21 m.y. until early Triassic (~239 Ma), that is faster than the Cenozoic major rise (0.00003/m.y.).　The most significant shift through Phanerozoic in Sr isotope trend can be explained by the remarkable changes in continental erosion/weathering rate; in particular, by the onset of glaciation and the following deglaciation, that is supported by global sea level change, in addition to the initial doming/rifting of Pangea. After the Capitanian cooling, the long-term climatic regime shifted to a warmer one during which inland ice sheet was removed to expose old crustal silicates for to erosion/weathering. A mantle plume impingiment might lead a domal uplift that accelerate weathering. Highly radiogenic continental Sr could enter the ocean along the new drainage systems developed with the rifting.

Global loudness of rising- and falling-intensity tones: How temporal profile characteristics shape overall judgments.

PubMed

Ponsot, Emmanuel; Susini, Patrick; Meunier, Sabine

2017-07-01

The mechanisms underlying global loudness judgments of rising- or falling-intensity tones were further investigated in two magnitude estimation experiments. By manipulating the temporal characteristics of such stimuli, it was examined whether judgments could be accounted for by an integration of their loudest portion over a certain temporal window associated to a "decay mechanism" downsizing this integration over time for falling ramps. In experiment 1, 1-kHz intensity-ramps were stretched in time between 1 and 16 s keeping their dynamics (difference between maximum and minimum levels) unchanged. While global loudness of rising tones increased up to 6 s, evaluations of falling tones increased at a weaker rate and slightly decayed between 6 and 16 s, resulting in significant differences between the two patterns. In experiment 2, ramps were stretched in time between 2 and 12 s keeping their slopes (rate of change in dB/s) unchanged. In this context, the main effect of duration became non-significant and the interaction between the two profiles remained, although the decay of falling tones was not significant. These results qualitatively support the view that the global loudness computation of intensity-ramps involves an integration of their loudest portions; the presence of a decay mechanism could, however, not be attested.

A distance-independent calibration of the luminosity of type Ia supernovae and the Hubble constant

NASA Technical Reports Server (NTRS)

Leibundgut, Bruno; Pinto, Philip A.

1992-01-01

The absolute magnitude of SNe Ia at maximum is calibrated here using radioactive decay models for the light curve and a minimum of assumptions. The absolute magnitude parameter space is studied using explosion models and a range of rise times, and absolute B magnitudes at maximum are used to derive a range of the H0 and the distance to the Virgo Cluster from SNe Ia. Rigorous limits for H0 of 45 and 105 km/s/Mpc are derived.

77 FR 46034 - Utility Scale Wind Towers From the People's Republic of China: Preliminary Determination of Sales...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-02

... nacelle and rotor blades in a wind turbine with a minimum rated electrical power generation capacity in... efficiencies have been improving, and turbine heights have been rising to altitudes with much stronger winds... configurations that meet the minimum height requirement and are designed to support wind turbine electrical...

Simulating the Outer Radiation Belt During the Rising Phase of Solar Cycle 24

NASA Technical Reports Server (NTRS)

Fok, Mei-Ching; Glocer, Alex; Zheng, Qiuhua; Chen, Sheng-Hsien; Kanekal, Shri; Nagai, Tsungunobu; Albert, Jay

2011-01-01

After prolonged period of solar minimum, there has been an increase in solar activity and its terrestrial consequences. We are in the midst of the rising phase of solar cycle 24, which began in January 2008. During the initial portion of the cycle, moderate geomagnetic storms occurred follow the 27 day solar rotation. Most of the storms were accompanied by increases in electron fluxes in the outer radiation belt. These enhancements were often preceded with rapid dropout at high L shells. We seek to understand the similarities and differences in radiation belt behavior during the active times observed during the of this solar cycle. This study includes extensive data and simulations our Radiation Belt Environment Model. We identify the processes, transport and wave-particle interactions, that are responsible for the flux dropout and the enhancement and recovery.

Increased minimum legal age for the sale of alcohol in the Netherlands as of 2014: The effect on alcohol sellers' compliance after one and two years.

PubMed

Schelleman-Offermans, Karen; Roodbeen, Ruud T J; Lemmens, Paul H H M

2017-11-01

As of January 2014, the Dutch minimum legal age for the sale and purchase of all alcoholic beverages has increased from 16 to 18 years of age. The effectiveness of a minimum legal age policy in controlling the availability of alcohol for adolescents depends on the extent to which this minimum legal age is complied with in the field. The main aim of the current study is to investigate, for a country with a West-European drinking culture, whether raising the minimum legal age for the sale of alcohol has influenced compliance rates among Dutch alcohol vendors. A total of 1770 alcohol purchase attempts by 15-year-old mystery shoppers were conducted in three independent Dutch representative samples of on- and off-premise alcohol outlets in 2013 (T0), 2014 (T1), and 2016 (T2). The effect of the policy change was estimated controlling for gender and age of the vendor. Mean alcohol sellers' compliance rates significantly increased for 15-year-olds from 46.5% before to 55.7% one year and to 73.9% two years after the policy change. Two years after the policy change, alcohol vendors were up to 3 times more likely to comply with the alcohol age limit policy. After the policy change, mean alcohol compliance rates significantly increased when 15-year-olds attempted to purchase alcohol, an effect which seems to increase over time. Nevertheless, a rise in the compliance rate was already present in the years preceding the introduction of the new minimum legal age. This perhaps signifies a process in which a lowering in the general acceptability of juvenile drinking already started before the increased minimum legal age was introduced and alcohol vendors might have been anticipating this formal legal change. Copyright © 2017 Elsevier B.V. All rights reserved.

Herbarium specimens, photographs, and field observations show Philadelphia area plants are responding to climate change.

PubMed

Panchen, Zoe A; Primack, Richard B; Anisko, Tomasz; Lyons, Robert E

2012-04-01

The global climate is changing rapidly and is expected to continue changing in coming decades. Studying changes in plant flowering times during a historical period of warming temperatures gives us a way to examine the impacts of climate change and allows us to predict further changes in coming decades. The Greater Philadelphia region has a long and rich history of botanical study and documentation, with abundant herbarium specimens, field observations, and botanical photographs from the mid-1800s onward. These extensive records also provide an opportunity to validate methodologies employed by other climate change researchers at a different biogeographical area and with a different group of species. Data for 2539 flowering records from 1840 to 2010 were assessed to examine changes in flowering response over time and in relation to monthly minimum temperatures of 28 Piedmont species native to the Greater Philadelphia region. Regression analysis of the date of flowering with year or with temperature showed that, on average, the Greater Philadelphia species studied are flowering 16 d earlier over the 170-yr period and 2.7 d earlier per 1°C rise in monthly minimum temperature. Of the species studied, woody plants with short flowering duration are the best indicators of a warming climate. For monthly minimum temperatures, temperatures 1 or 2 mo prior to flowering are most significantly correlated with flowering time. Studies combining herbarium specimens, photographs, and field observations are an effective method for detecting the effects of climate change on flowering times.

An evaluation of Appalachian Trail hikers' knowledge of minimum impact skills and practices

Treesearch

Peter Newman; Robert Manning; Jim Bacon; Alan Graefe; Gerard Kyle

2002-01-01

As the number of visitors to national parks and related areas continues to rise and the types of visitors and activities continue to diversify, educating visitors in minimum skills can help to protect parks and related areas. Educating visitors in these skills can be a challenge, especially on the Appalachian Trail (AT) that travels through state, federal, municipal...

Time trends in minimum mortality temperatures in Castile-La Mancha (Central Spain): 1975-2003

NASA Astrophysics Data System (ADS)

Miron, Isidro J.; Criado-Alvarez, Juan José; Diaz, Julio; Linares, Cristina; Mayoral, Sheila; Montero, Juan Carlos

2008-03-01

The relationship between air temperature and human mortality is described as non-linear, with mortality tending to rise in response to increasingly hot or cold ambient temperatures from a given minimum mortality or optimal comfort temperature, which varies from some areas to others according to their climatic and socio-demographic characteristics. Changes in these characteristics within any specific region could modify this relationship. This study sought to examine the time trend in the maximum temperature of minimum organic-cause mortality in Castile-La Mancha, from 1975 to 2003. The analysis was performed by using daily series of maximum temperatures and organic-cause mortality rates grouped into three decades (1975-1984, 1985-1994, 1995-2003) to compare confidence intervals ( p < 0.05) obtained by estimating the 10-yearly mortality rates corresponding to the maximum temperatures of minimum mortality calculated for each decade. Temporal variations in the effects of cold and heat on mortality were ascertained by means of ARIMA models (Box-Jenkins) and cross-correlation functions (CCF) at seven lags. We observed a significant decrease in comfort temperature (from 34.2°C to 27.8°C) between the first two decades in the Province of Toledo, along with a growing number of significant lags in the summer CFF (1, 3 and 5, respectively). The fall in comfort temperature is attributable to the increase in the effects of heat on mortality, due, in all likelihood, to the percentage increase in the elderly population.

The minimum or natural rate of flow and droplet size ejected by Taylor cone-jets: physical symmetries and scaling laws

NASA Astrophysics Data System (ADS)

Gañán-Calvo, A. M.; Rebollo-Muñoz, N.; Montanero, J. M.

2013-03-01

We aim to establish the scaling laws for both the minimum rate of flow attainable in the steady cone-jet mode of electrospray, and the size of the resulting droplets in that limit. Use is made of a small body of literature on Taylor cone-jets reporting precise measurements of the transported electric current and droplet size as a function of the liquid properties and flow rate. The projection of the data onto an appropriate non-dimensional parameter space maps a region bounded by the minimum rate of flow attainable in the steady state. To explain these experimental results, we propose a theoretical model based on the generalized concept of physical symmetry, stemming from the system time invariance (steadiness). A group of symmetries rising at the cone-to-jet geometrical transition determines the scaling for the minimum flow rate and related variables. If the flow rate is decreased below that minimum value, those symmetries break down, which leads to dripping. We find that the system exhibits two instability mechanisms depending on the nature of the forces arising against the flow: one dominated by viscosity and the other by the liquid polarity. In the former case, full charge relaxation is guaranteed down to the minimum flow rate, while in the latter the instability condition becomes equivalent to the symmetry breakdown by charge relaxation or separation. When cone-jets are formed without artificially imposing a flow rate, a microjet is issued quasi-steadily. The flow rate naturally ejected this way coincides with the minimum flow rate studied here. This natural flow rate determines the minimum droplet size that can be steadily produced by any electrohydrodynamic means for a given set of liquid properties.

Brief Report: Investigating Uncertainty in the Minimum Mortality Temperature: Methods and Application to 52 Spanish Cities.

PubMed

Tobías, Aurelio; Armstrong, Ben; Gasparrini, Antonio

2017-01-01

The minimum mortality temperature from J- or U-shaped curves varies across cities with different climates. This variation conveys information on adaptation, but ability to characterize is limited by the absence of a method to describe uncertainty in estimated minimum mortality temperatures. We propose an approximate parametric bootstrap estimator of confidence interval (CI) and standard error (SE) for the minimum mortality temperature from a temperature-mortality shape estimated by splines. The coverage of the estimated CIs was close to nominal value (95%) in the datasets simulated, although SEs were slightly high. Applying the method to 52 Spanish provincial capital cities showed larger minimum mortality temperatures in hotter cities, rising almost exactly at the same rate as annual mean temperature. The method proposed for computing CIs and SEs for minimums from spline curves allows comparing minimum mortality temperatures in different cities and investigating their associations with climate properly, allowing for estimation uncertainty.

Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study.

PubMed

Master, Hiral; Thoma, Louise M; Christiansen, Meredith B; Polakowski, Emily; Schmitt, Laura A; White, Daniel K

2018-07-01

Evidence of physical function difficulties, such as difficulty rising from a chair, may limit daily walking for people with knee osteoarthritis (OA). The purpose of this study was to identify minimum performance thresholds on clinical tests of physical function predictive to walking ≥6,000 steps/day. This benchmark is known to discriminate people with knee OA who develop functional limitation over time from those who do not. Using data from the Osteoarthritis Initiative, we quantified daily walking as average steps/day from an accelerometer (Actigraph GT1M) worn for ≥10 hours/day over 1 week. Physical function was quantified using 3 performance-based clinical tests: 5 times sit-to-stand test, walking speed (tested over 20 meters), and 400-meter walk test. To identify minimum performance thresholds for daily walking, we calculated physical function values corresponding to high specificity (80-95%) to predict walking ≥6,000 steps/day. Among 1,925 participants (mean ± SD age 65.1 ± 9.1 years, mean ± SD body mass index 28.4 ± 4.8 kg/m 2 , and 55% female) with valid accelerometer data, 54.9% walked ≥6,000 steps/day. High specificity thresholds of physical function for walking ≥6,000 steps/day ranged 11.4-14.0 seconds on the 5 times sit-to-stand test, 1.13-1.26 meters/second for walking speed, or 315-349 seconds on the 400-meter walk test. Not meeting these minimum performance thresholds on clinical tests of physical function may indicate inadequate physical ability to walk ≥6,000 steps/day for people with knee OA. Rehabilitation may be indicated to address underlying impairments limiting physical function. © 2017, American College of Rheumatology.

Postinflationary Higgs relaxation and the origin of matter-antimatter asymmetry.

PubMed

Kusenko, Alexander; Pearce, Lauren; Yang, Louis

2015-02-13

The recent measurement of the Higgs boson mass implies a relatively slow rise of the standard model Higgs potential at large scales, and a possible second minimum at even larger scales. Consequently, the Higgs field may develop a large vacuum expectation value during inflation. The relaxation of the Higgs field from its large postinflationary value to the minimum of the effective potential represents an important stage in the evolution of the Universe. During this epoch, the time-dependent Higgs condensate can create an effective chemical potential for the lepton number, leading to a generation of the lepton asymmetry in the presence of some large right-handed Majorana neutrino masses. The electroweak sphalerons redistribute this asymmetry between leptons and baryons. This Higgs relaxation leptogenesis can explain the observed matter-antimatter asymmetry of the Universe even if the standard model is valid up to the scale of inflation, and any new physics is suppressed by that high scale.

Experimental study of the nonlinear diffusion of a magnetic field and skin explosion of cylindrical conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaikovsky, S. A.; Datsko, I. M.; Labetskaya, N. A.

The paper presents the results of an experimental study of the skin explosion of cylindrical conductors of diameter 1–3 mm (copper, aluminum, titanium, steel 3, and stainless steel) at a peak magnetic field of 200–600 T. The experiments were carried out on the MIG pulsed power generator at a current of up to 2.5 MA and a current rise time of 100 ns. The surface explosion of a conductor was identified by the appearance of a flash of extreme ultraviolet radiation. A minimum magnetic induction has been determined below which no plasma is generated at the conductor surface. For copper, aluminum, steel 3,more » titanium, and stainless steel, the minimum magnetic induction has been estimated to be (to within 10%) 375, 270, 280, 220, and 245 T, respectively.« less

Greenland-Wide Seasonal Temperatures During the Last Deglaciation

NASA Astrophysics Data System (ADS)

Buizert, C.; Keisling, B. A.; Box, J. E.; He, F.; Carlson, A. E.; Sinclair, G.; DeConto, R. M.

2018-02-01

The sensitivity of the Greenland ice sheet to climate forcing is of key importance in assessing its contribution to past and future sea level rise. Surface mass loss occurs during summer, and accounting for temperature seasonality is critical in simulating ice sheet evolution and in interpreting glacial landforms and chronologies. Ice core records constrain the timing and magnitude of climate change but are largely limited to annual mean estimates from the ice sheet interior. Here we merge ice core reconstructions with transient climate model simulations to generate Greenland-wide and seasonally resolved surface air temperature fields during the last deglaciation. Greenland summer temperatures peak in the early Holocene, consistent with records of ice core melt layers. We perform deglacial Greenland ice sheet model simulations to demonstrate that accounting for realistic temperature seasonality decreases simulated glacial ice volume, expedites the deglacial margin retreat, mutes the impact of abrupt climate warming, and gives rise to a clear Holocene ice volume minimum.

Vulnerability assessment of the impact of sea-level rise and flooding on the Moroccan coast: The case of the Mediterranean eastern zone

NASA Astrophysics Data System (ADS)

Snoussi, Maria; Ouchani, Tachfine; Niazi, Saïda

2008-04-01

The eastern part of the Mediterranean coast of Morocco is physically and socio-economically vulnerable to accelerated sea-level rise, due to its low topography and its high ecological and touristic value. Assessment of the potential land loss by inundation has been based on empirical approaches using a minimum inundation level of 2 m and a maximum inundation level of 7 m, where scenarios for future sea-level rise range from 200 to 860 mm, with a 'best estimate' of 490 mm. The socio-economic impacts have been based on two possible alternative futures: (1) a 'worst-case' scenario, obtained by combining the 'economic development first' scenario with the maximum inundation level; and (2) a 'best-case' scenario, by combining the 'sustainability first' scenario with the minimum inundation level. Inundation analysis, based on Geographical Information Systems and a modelling approach to erosion, has identified both locations and the socioeconomic sectors that are most at risk to accelerated sea-level rise. Results indicate that 24% and 59% of the area will be lost by flooding at minimum and maximum inundation levels, respectively. The most severely impacted sectors are expected to be the residential and recreational areas, agricultural land, and the natural ecosystem. Shoreline erosion will affect 50% and 70% of the total area in 2050 and 2100, respectively. Potential strategies to ameliorate the impact of seawater inundation include: wetland preservation; beach nourishment at tourist resorts; and the afforestation of dunes. As this coast is planned to become one of the most developed tourist resorts in Morocco by 2010, measures such as building regulation, urban growth planning and development of an Integrated Coastal Zone Management Plan, are recommended for the region.

Hemispheric Sunspot Unit Area: Comparison with Hemispheric Sunspot Number and Sunspot Area

NASA Astrophysics Data System (ADS)

Li, K. J.; Xiang, N. B.; Qu, Z. N.; Xie, J. L.

2014-03-01

The monthly mean northern and southern hemispheric sunspot numbers (SNs) and sunspot areas (SAs) in the time interval of 1945 January to 2012 December are utilized to construct the monthly northern and southern hemispheric sunspot unit areas (SUAs), which are defined as the ratio of hemispheric SA to SN. Hemispheric SUAs are usually found to rise at the beginning and to fall at the ending time of a solar cycle more rapidly, forming a more irregular cycle profile than hemispheric SNs and SAs, although it also presents Schwabe-cycle-like hemispheric SNs and SAs. Sunspot activity (SN, SA, and SUA) is found asynchronously and is asymmetrically distributed in the northern and southern hemispheres, and hemispheric SNs, SAs, and SUAs are not in phase in the two hemispheres. The similarity of hemispheric SNs and SAs is found to be much more obvious than that of hemispheric SUAs and SNs (or SAs), and also for their north-south asymmetry. A notable feature is found for the behavior of the SUA around the minimum time of cycle 24: the SUA rapidly decreases from the cycle maximum value to the cycle minimum value of sunspot cycles 19-24 within just 22 months.

Hemispheric sunspot unit area: comparison with hemispheric sunspot number and sunspot area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, K. J.; Xiang, N. B.; Qu, Z. N.

2014-03-01

The monthly mean northern and southern hemispheric sunspot numbers (SNs) and sunspot areas (SAs) in the time interval of 1945 January to 2012 December are utilized to construct the monthly northern and southern hemispheric sunspot unit areas (SUAs), which are defined as the ratio of hemispheric SA to SN. Hemispheric SUAs are usually found to rise at the beginning and to fall at the ending time of a solar cycle more rapidly, forming a more irregular cycle profile than hemispheric SNs and SAs, although it also presents Schwabe-cycle-like hemispheric SNs and SAs. Sunspot activity (SN, SA, and SUA) is foundmore » asynchronously and is asymmetrically distributed in the northern and southern hemispheres, and hemispheric SNs, SAs, and SUAs are not in phase in the two hemispheres. The similarity of hemispheric SNs and SAs is found to be much more obvious than that of hemispheric SUAs and SNs (or SAs), and also for their north-south asymmetry. A notable feature is found for the behavior of the SUA around the minimum time of cycle 24: the SUA rapidly decreases from the cycle maximum value to the cycle minimum value of sunspot cycles 19-24 within just 22 months.« less

Flight Demonstration of a Shock Location Sensor Using Constant Voltage Hot-Film Anemometry

NASA Technical Reports Server (NTRS)

Moes, Timothy R.; Sarma, Garimella R.; Mangalam, Siva M.

1997-01-01

Flight tests have demonstrated the effectiveness of an array of hot-film sensors using constant voltage anemometry to determine shock position on a wing or aircraft surface at transonic speeds. Flights were conducted at the NASA Dryden Flight Research Center using the F-15B aircraft and Flight Test Fixture (FTF). A modified NACA 0021 airfoil was attached to the side of the FTF, and its upper surface was instrumented to correlate shock position with pressure and hot-film sensors. In the vicinity of the shock-induced pressure rise, test results consistently showed the presence of a minimum voltage in the hot-film anemometer outputs. Comparing these results with previous investigations indicate that hot-film anemometry can identify the location of the shock-induced boundary layer separation. The flow separation occurred slightly forward of the shock- induced pressure rise for a laminar boundary layer and slightly aft of the start of the pressure rise when the boundary layer was tripped near the airfoil leading edge. Both minimum mean output and phase reversal analyses were used to identify the shock location.

Excited state intramolecular charge transfer reaction in binary mixtures of water and tertiary butanol (TBA): alcohol mole fraction dependence.

PubMed

Pradhan, Tuhin; Ghoshal, Piue; Biswas, Ranjit

2008-02-07

The excited state intramolecular charge transfer reaction of 4-(1-azetidinyl)benzonitrile (P4C) has been studied in water-tertiary butanol (TBA) mixtures at different alcohol mole fractions by using steady state and time-resolved fluorescence spectroscopy. The ratio between the areas under the locally excited (LE) and charge transferred (CT) emission bands is found to exhibit a sharp rise at alcohol mole fraction approximately 0.04, a value at which several thermodynamic properties of this mixture is known to show anomalous change due to the enhancement of H-bonding network. The radiative rate associated with the LE emission also shows a maximum at this TBA mole fraction. Although the structural transition from the water-like tetrahedral network to the alcohol-like chain is reflected in the red shift of the absorption spectrum up to TBA mole fraction approximately 0.10, the emission bands (both LE and CT) show the typical nonideal alcohol mole fraction dependence at all TBA mole fractions. Quantum yield, CT radiative rate as well as transition moments also exhibit a nonideal alcohol mole fraction dependence. The time-resolved emission decay of P4C has been found to be biexponential at all TBA mole fractions, regardless of emission collection around either the LE or the CT bands. The time constant associated with the slow component (tau(slow)) shows a minimum at TBA mole fraction approximately 0.04, whereas such a minimum for the fast time constant, tau(fast) (representing the rate of LE --> CT conversion reaction) is not observed. The nonobservation of the minimum in tau(fast) might be due to the limited time resolution employed in our experiments.

Prostate specific antigen velocity as a measure of the natural history of prostate cancer: defining a 'rapid riser' subset.

PubMed

Nam, R K; Klotz, L H; Jewett, M A; Danjoux, C; Trachtenberg, J

1998-01-01

To study the rate of change in prostate specific antigen (PSA velocity) in patients with prostate cancer initially managed by 'watchful waiting'. Serial PSA levels were determined in 141 patients with prostate cancer confirmed by biopsy, who were initially managed expectantly and enrolled between May 1990 and December 1995. Sixty-seven patients eventually underwent surgery (mean age 59 years) because they chose it (the decision for surgery was not based on PSA velocity). A cohort of 74 patients remained on 'watchful waiting' (mean age 69 years). Linear regression and logarithmic transformations were used to segregate those patients who showed a rapid rise, defined as a > 50% rise in PSA per year (or a doubling time of < 2 years) and designated 'rapid risers'. An initial analysis based on a minimum of two PSA values showed that 31% were rapid risers. Only 15% of patients with more than three serial PSA determinations over > or = 6 months showed a rapid rise in PSA level. There was no advantage of log-linear analysis over linear regression models. Three serial PSA determinations over > or = 6 months in patients with clinically localized prostate cancer identifies a subset (15%) of patients with a rapidly rising PSA level. Shorter PSA surveillance with fewer PSA values may falsely identify patients with rapid rises in PSA level. However, further follow-up is required to determine if a rapid rise in PSA level identifies a subset of patients with an aggressive biological phenotype who are either still curable or who have already progressed to incurability through metastatic disease.

How unprecedented a solar minimum was it?

PubMed

Russell, C T; Jian, L K; Luhmann, J G

2013-05-01

The end of the last solar cycle was at least 3 years late, and to date, the new solar cycle has seen mainly weaker activity since the onset of the rising phase toward the new solar maximum. The newspapers now even report when auroras are seen in Norway. This paper is an update of our review paper written during the deepest part of the last solar minimum [1]. We update the records of solar activity and its consequent effects on the interplanetary fields and solar wind density. The arrival of solar minimum allows us to use two techniques that predict sunspot maximum from readings obtained at solar minimum. It is clear that the Sun is still behaving strangely compared to the last few solar minima even though we are well beyond the minimum phase of the cycle 23-24 transition.

[Home health resource utilization measures using a case-mix adjustor model].

PubMed

You, Sun-Ju; Chang, Hyun-Sook

2005-08-01

The purpose of this study was to measure home health resource utilization using a Case-Mix Adjustor Model developed in the U.S. The subjects of this study were 484 patients who had received home health care more than 4 visits during a 60-day episode at 31 home health care institutions. Data on the 484 patients had to be merged onto a 60-day payment segment. Based on the results, the researcher classified home health resource groups (HHRG). The subjects were classified into 34 HHRGs in Korea. Home health resource utilization according to clinical severity was in order of Minimum (C0) < 'Low (C1) < 'Moderate (C2) < 'High (C3), according to dependency in daily activities was in order of Minimum (F0) < 'High (F3) < 'Medium (F2) < 'Low (F1) < 'Maximum (F4). Resource utilization by HHRGs was the highest 564,735 won in group C0F0S2 (clinical severity minimum, dependency in daily activity minimum, service utilization moderate), and the lowest 97,000 won in group C2F3S1, so the former was 5.82 times higher than the latter. Resource utilization in home health care has become an issue of concern due to rising costs for home health care. The results suggest the need for more analytical attention on the utilization and expenditures for home care using a Case-Mix Adjustor Model.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Pisin; Hsin, Po-Shen; Niu, Yuezhen, E-mail: pisinchen@phys.ntu.edu.tw, E-mail: r01222031@ntu.edu.tw, E-mail: yuezhenniu@gmail.com

We investigate the entropy evolution in the early universe by computing the change of the entanglement entropy in Freedmann-Robertson-Walker quantum cosmology in the presence of particle horizon. The matter is modeled by a Chaplygin gas so as to provide a smooth interpolation between inflationary and radiation epochs, rendering the evolution of entropy from early time to late time trackable. We found that soon after the onset of the inflation, the total entanglement entropy rapidly decreases to a minimum. It then rises monotonically in the remainder of the inflation epoch as well as the radiation epoch. Our result is in qualitativemore » agreement with the area law of Ryu and Takayanagi including the logarithmic correction. We comment on the possible implication of our finding to the cosmological entropy problem.« less

[Space-time water monitoring system at the Iriklinsk hydroelectric power station].

PubMed

Deriabin, D G; Poliakov, E G; Priakhina, A A; Karimov, I F

2002-01-01

The Microbiosensor B 17677 F test system was applied to make a space-time monitoring of the biotoxicity of water used for production and everyday purposes at the Iriklinsk hydroelectric power station (IHEPS) and to identify the leading causes determining the biotoxicity of tested samples. There were seasonal variations in the biotoxicity with the maximum in spring and with minimum in winter and spring and a relationship of the spring rise in the biotoxicity to water pH changes. There was also an association of the certain values of the biotoxicity of industrial water with the concentration of petroleum products that are major pollutants at the IHEPS. The datum points that characterize the maximum level of technogenic exposure were identified.

Minimum weight passive insulation requirements for hypersonic cruise vehicles.

NASA Technical Reports Server (NTRS)

Ardema, M. D.

1972-01-01

Analytical solutions are derived for two representative cases of the transient heat conduction equation to determine the minimum weight requirements for passive insulation systems of hypersonic cruise vehicles. The cases discussed are the wet wall case with the interior wall temperature held to that of the boiling point of the fuel throughout the flight, and the dry wall case where the heat transferred through the insulation is absorbed by the interior structure whose temperature is allowed to rise.

On pressure measurement and seasonal pressure variations during the Phoenix mission

NASA Astrophysics Data System (ADS)

Taylor, Peter A.; Kahanpää, Henrik; Weng, Wensong; Akingunola, Ayodeji; Cook, Clive; Daly, Mike; Dickinson, Cameron; Harri, Ari-Matti; Hill, Darren; Hipkin, Victoria; Polkko, Jouni; Whiteway, Jim

2010-03-01

In situ surface pressures measured at 2 s intervals during the 150 sol Phoenix mission are presented and seasonal variations discussed. The lightweight Barocap®/Thermocap® pressure sensor system performed moderately well. However, the original data processing routine had problems because the thermal environment of the sensor was subject to more rapid variations than had been expected. Hence, the data processing routine was updated after Phoenix landed. Further evaluation and the development of a correction are needed since the temperature dependences of the Barocap sensor heads have drifted after the calibration of the sensor. The inaccuracy caused by this appears when the temperature of the unit rises above 0°C. This frequently affects data in the afternoons and precludes a full study of diurnal pressure variations at this time. Short-term fluctuations, on time scales of order 20 s are unaffected and are reported in a separate paper in this issue. Seasonal variations are not significantly affected by this problem and show general agreement with previous measurements from Mars. During the 151 sol mission the surface pressure dropped from around 860 Pa to a minimum (daily average) of 724 Pa on sol 140 (Ls 143). This local minimum occurred several sols earlier than expected based on GCM studies and Viking data. Since battery power was lost on sol 151 we are not sure if the timing of the minimum that we saw could have been advanced by a low-pressure meteorological event. On sol 95 (Ls 122), we also saw a relatively low-pressure feature. This was accompanied by a large number of vertical vortex events, characterized by short, localized (in time), low-pressure perturbations.

Reactive Resonances in N+N2 Exchange Reaction

NASA Technical Reports Server (NTRS)

Wang, Dunyou; Huo, Winifred M.; Dateo, Christopher E.; Schwenke, David W.; Stallcop, James R.

2003-01-01

Rich reactive resonances are found in a 3D quantum dynamics study of the N + N2 exchange reaction using a recently developed ab initio potential energy surface. This surface is characterized by a feature in the interaction region called Lake Eyring , that is, two symmetric transition states with a shallow minimum between them. An L2 analysis of the quasibound states associated with the shallow minimum confirms that the quasibound states associated with oscillations in all three degrees of freedom in Lake Eyring are responsible for the reactive resonances in the state-to-state reaction probabilities. The quasibound states, mostly the bending motions, give rise to strong reasonance peaks, whereas other motions contribute to the bumps and shoulders in the resonance structure. The initial state reaction probability further proves that the bending motions are the dominating factors of the reaction probability and have longer life times than the stretching motions. This is the first observation of reactive resonances from a "Lake Eyring" feature in a potential energy surface.

Evolution of canine parvovirus--a need for new vaccines?

PubMed

Truyen, Uwe

2006-10-05

Canine parvovirus (CPV) is a new virus, which is continuing to evolve, giving rise to new antigenic types and virus mutants that spread through the dog population. The most successful mutants, from an evolutionary perspective, appear to be selected by improved binding to the CPV receptor, the canine transferrin receptor, and by an extended host range, which for the newer antigenic types now includes both the dog and the cat. The new viruses also show antigenic differences that can be defined by binding of certain monoclonal antibodies; they also differ in their reactivity in virus neutralisation tests, using immune sera raised against the various antigenic types. These differences may influence the susceptibility of young animals to infection at the time when the level of maternally derived antibody decreases to the minimum protective titre. This minimum protective titre may vary depending on the infecting virus type. There is, however, a high degree of cross-protection between the virus types and the true relevance of the differences in neutralisation titer is currently not known.

Backwater effects in the Amazon River basin of Brazil

USGS Publications Warehouse

Meade, R.H.; Rayol, J.M.; Da Conceicao, S.C.; Natividade, J.R.G.

1991-01-01

The Amazon River mainstem of Brazil is so regulated by differences in the timing of tributary inputs and by seasonal storage of water on floodplains that maximum discharges exceed minimum discharges by a factor of only 3. Large tributaries that drain the southern Amazon River basin reach their peak discharges two months earlier than does the mainstem. The resulting backwater in the lowermost 800 km of two large southern tributaries, the Madeira and Puru??s rivers, causes falling river stages to be as much as 2-3 m higher than rising stages at any given discharge. Large tributaries that drain the northernmost Amazon River basin reach their annual minimum discharges three to four months later than does the mainstem. In the lowermost 300-400 km of the Negro River, the largest northern tributary and the fifth largest river in the world, the lowest stages of the year correspond to those of the Amazon River mainstem rather than to those in the upstream reaches of the Negro River. ?? 1991 Springer-Verlag New York Inc.

Test beam measurement of the first prototype of the fast silicon pixel monolithic detector for the TT-PET project

NASA Astrophysics Data System (ADS)

Paolozzi, L.; Bandi, Y.; Benoit, M.; Cardarelli, R.; Débieux, S.; Forshaw, D.; Hayakawa, D.; Iacobucci, G.; Kaynak, M.; Miucci, A.; Nessi, M.; Ratib, O.; Ripiccini, E.; Rücker, H.; Valerio, P.; Weber, M.

2018-04-01

The TT-PET collaboration is developing a PET scanner for small animals with 30 ps time-of-flight resolution and sub-millimetre 3D detection granularity. The sensitive element of the scanner is a monolithic silicon pixel detector based on state-of-the-art SiGe BiCMOS technology. The first ASIC prototype for the TT-PET was produced and tested in the laboratory and with minimum ionizing particles. The electronics exhibit an equivalent noise charge below 600 e‑ RMS and a pulse rise time of less than 2 ns , in accordance with the simulations. The pixels with a capacitance of 0.8 pF were measured to have a detection efficiency greater than 99% and, although in the absence of the post-processing, a time resolution of approximately 200 ps .

Detecting anthropogenic footprints in sea level rise: the role of complex colored noise

NASA Astrophysics Data System (ADS)

Dangendorf, Sönke; Marcos, Marta; Müller, Alfred; Zorita, Eduardo; Jensen, Jürgen

2015-04-01

While there is scientific consensus that global mean sea level (MSL) is rising since the late 19th century, it remains unclear how much of this rise is due to natural variability or anthropogenic forcing. Uncovering the anthropogenic contribution requires profound knowledge about the persistence of natural MSL variations. This is challenging, since observational time series represent the superposition of various processes with different spectral properties. Here we statistically estimate the upper bounds of naturally forced centennial MSL trends on the basis of two separate components: a slowly varying volumetric (mass and density changes) and a more rapidly changing atmospheric component. Resting on a combination of spectral analyses of tide gauge records, ocean reanalysis data and numerical Monte-Carlo experiments, we find that in records where transient atmospheric processes dominate, the persistence of natural volumetric changes is underestimated. If each component is assessed separately, natural centennial trends are locally up to ~0.5 mm/yr larger than in case of an integrated assessment. This implies that external trends in MSL rise related to anthropogenic forcing might be generally overestimated. By applying our approach to the outputs of a centennial ocean reanalysis (SODA), we estimate maximum natural trends in the order of 1 mm/yr for the global average. This value is larger than previous estimates, but consistent with recent paleo evidence from periods in which the anthropogenic contribution was absent. Comparing our estimate to the observed 20th century MSL rise of 1.7 mm/yr suggests a minimum external contribution of at least 0.7 mm/yr. We conclude that an accurate detection of anthropogenic footprints in MSL rise requires a more careful assessment of the persistence of intrinsic natural variability.

A proof of the theorem regarding the distribution of lift over the span for minimum induced drag

NASA Technical Reports Server (NTRS)

Durand, W F

1931-01-01

The proof of the theorem that the elliptical distribution of lift over the span is that which will give rise to the minimum induced drag has been given in a variety of ways, generally speaking too difficult to be readily followed by the graduate of the average good technical school of the present day. In the form of proof this report makes an effort to bring the matter more readily within the grasp of this class of readers.

Military Occupational Speciality Training Cost Handbook (MOSB)

DTIC Science & Technology

1983-10-01

FINANCE & ACCOUNTING CENTER "JUN 1 i 184’, l APPROVED:_ . A " W. M. ALLENi T - DIRECTOR OF COST ANALYSIS _ "OFFICE OF THE COMPTROLLER OF THE ARMYj 84 04 16 ...COVERED j14. DATE OF REPORT (Yr.. Alo.. Day) 15 AE COUNT 16 . SUPPLEMENTARY NOTAOMION IFROM TO 83/10 43o Supersedes Volumes I and II, MOSB, dated 81... depreciation of equipment, minimum consumption of utilities, pay of minimum grounds staff, etc. Of course, per capita fixed cost will rise with a decreasing

77 FR 71735 - Minimum Altitudes for Use of Autopilots

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-04

... Generation Air Transportation System (NextGen) technologies and procedures (Optimized Profile Descents... altitudes for use of autopilots were unduly restrictive and would limit the ability to use new technologies..., including the rise of new technologies.'' [[Page 71736

Sunspot Time Series - Relations Inferred from the Location of the Longest Spotless Segments

NASA Astrophysics Data System (ADS)

Zięba, Stanisław; Nieckarz, Zenon

2012-06-01

Spotless days ( i.e., days when no sunspots are observed on the Sun) occur during the interval between the declining phase of the old sunspot cycle and the rising phase of the new sunspot cycle, being greatest in number and of longest continuous length near a new cycle minimum. In this paper, we introduce the concept of the longest spotless segment (LSS) and examine its statistical relation to selected characteristic points in the sunspot time series (STS), such as the occurrences of first spotless day and sunspot maximum. The analysis has revealed statistically significant relations that appear to be of predictive value. For example, for Cycle 24 the last spotless day during its rising phase should be about August 2012 (± 9.1 months), the daily maximum sunspot number should be about 227 (± 50; occurring about January 2014±9.5 months), and the maximum Gaussian smoothed sunspot number should be about 87 (± 25; occurring about July 2014). Using the Gaussian-filtered values, slightly earlier dates of August 2011 and March 2013 are indicated for the last spotless day and sunspot maximum for Cycle 24, respectively.

The observable signature of late heating of the Universe during cosmic reionization.

PubMed

Fialkov, Anastasia; Barkana, Rennan; Visbal, Eli

2014-02-13

Models and simulations of the epoch of reionization predict that spectra of the 21-centimetre transition of atomic hydrogen will show a clear fluctuation peak, at a redshift and scale, respectively, that mark the central stage of reionization and the characteristic size of ionized bubbles. This is based on the assumption that the cosmic gas was heated by stellar remnants-particularly X-ray binaries-to temperatures well above the cosmic microwave background at that time (about 30 kelvin). Here we show instead that the hard spectra (that is, spectra with more high-energy photons than low-energy photons) of X-ray binaries make such heating ineffective, resulting in a delayed and spatially uniform heating that modifies the 21-centimetre signature of reionization. Rather than looking for a simple rise and fall of the large-scale fluctuations (peaking at several millikelvin), we must expect a more complex signal also featuring a distinct minimum (at less than a millikelvin) that marks the rise of the cosmic mean gas temperature above the microwave background. Observing this signal, possibly with radio telescopes in operation today, will demonstrate the presence of a cosmic background of hard X-rays at that early time.

Minimum virgin binder limits in recycled superpave mixes in Kansas : technical summary.

DOT National Transportation Integrated Search

2016-07-01

Use of recycled materials in asphalt pavement has become widespread recently due : to rising costs of virgin binder and increased attention to sustainability. Historically, : recycled asphalt pavement (RAP) has been the most commonly used recycled ma...

Minimum virgin binder limits in recycled superpave mixes in Kansas : final report.

DOT National Transportation Integrated Search

2016-07-01

Use of recycled materials in asphalt pavement has become widespread recently due to rising costs of virgin : binder and increased attention to sustainability. Historically, recycled asphalt pavement (RAP) has been the most : commonly used recycled ma...

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1987-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Reduction of temperature rise in high-speed photography

NASA Technical Reports Server (NTRS)

Slater, Howard A.

1988-01-01

Information is provided on filtration with glass and infrared absorbing and reflecting filters. Glass and infrared filtration is a simple and effective method to reduce the radiation heat transfer associated with continuous high intensity tungsten lamps. The results of a filtration experiment are explained. The figures provide starting points for quantifying the effectiveness of various filters and associated light intensities. The combination of a spectrally selective reflector (hot or cold mirror) based on multilayer thin film principles and heat absorbing or infrared opaque glass results in the maximum reduction in temperature rise with a minimum of incident light loss. Use is recommended of a voltage regulator to further control temperature rise and incident light values.

Behavior of Solar Cycles 23 and 24 Revealed by Microwave Observations

NASA Technical Reports Server (NTRS)

Gopalswamy, N.; Yashiro, S.; Maekelae, P.; Michalek, G.; Shibasaki, K.; Hathaway, D. H.

2012-01-01

Using magnetic and microwave butterfly diagrams, we compare the behavior of solar polar regions to show that (1) the polar magnetic field and the microwave brightness temperature during solar minimum substantially diminished during the cycle 23/24 minimum compared to the 22/23 minimum. (2) The polar microwave brightness temperature (Tb) seems to be a good proxy for the underlying magnetic field strength (B). The analysis indicates a relationship, B = 0.0067Tb - 70, where B is in G and Tb in K. (3) Both the brightness temperature and the magnetic field strength show north-south asymmetry most of the time except for a short period during the maximum phase. (4) The rush-to-the-pole phenomenon observed in the prominence eruption (PE) activity seems to be complete in the northern hemisphere as of 2012 March. (5) The decline of the microwave brightness temperature in the north polar region to the quiet-Sun levels and the sustained PE activity poleward of 60degN suggest that solar maximum conditions have arrived at the northern hemisphere. The southern hemisphere continues to exhibit conditions corresponding to the rise phase of solar cycle 24. Key words: Sun: chromosphere Sun: coronal mass ejections (CMEs) Sun: filaments, prominences Sun: photosphere Sun: radio radiation Sun: surface magnetism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Müller, O., E-mail: o.mueller@uni-wuppertal.de; Lützenkirchen-Hecht, D.; Frahm, R.

A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiationmore » sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.« less

Hard disk drive based microsecond X-ray chopper for characterization of ionization chambers and photodiodes.

PubMed

Müller, O; Lützenkirchen-Hecht, D; Frahm, R

2015-03-01

A fast X-ray chopper capable of producing ms long X-ray pulses with a typical rise time of few μs was realized. It is ideally suited to investigate the temporal response of X-ray detectors with response times of the order of μs to ms, in particular, any kind of ionization chambers and large area photo diodes. The drive mechanism consists of a brushless DC motor and driver electronics from a common hard disk drive, keeping the cost at an absolute minimum. Due to its simple construction and small dimensions, this chopper operates at home lab based X-ray tubes and synchrotron radiation sources as well. The dynamics of the most important detectors used in time resolved X-ray absorption spectroscopy, namely, ionization chambers and Passivated Implanted Planar Silicon photodiodes, were investigated in detail. The results emphasize the applicability of this X-ray chopper.

Gauging the Nearness and Size of Cycle Minimum

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1997-01-01

By definition, the conventional onset for the start of a sunspot cycle is the time when smoothed sunspot number (i.e., the 12-month moving average) has decreased to its minimum value (called minimum amplitude) prior to the rise to its maximum value (called maximum amplitude) for the given sunspot cycle. On the basis (if the modern era sunspot cycles 10-22 and on the presumption that cycle 22 is a short-period cycle having a cycle length of 120 to 126 months (the observed range of short-period modern era cycles), conventional onset for cycle 23 should not occur until sometime between September 1996 and March 1997, certainly between June 1996 and June 1997, based on the 95-percent confidence level deduced from the mean and standard deviation of period for the sample of six short-pei-iod modern era cycles. Also, because the first occurrence of a new cycle, high-latitude (greater than or equal to 25 degrees) spot has always preceded conventional onset of the new cycle by at least 3 months (for the data-available interval of cycles 12-22), conventional onset for cycle 23 is not expected until about August 1996 or later, based on the first occurrence of a new cycle 23, high-latitude spot during the decline of old cycle 22 in May 1996. Although much excitement for an earlier-occurring minimum (about March 1996) for cycle 23 was voiced earlier this year, the present study shows that this exuberance is unfounded. The decline of cycle 22 continues to favor cycle 23 minimum sometime during the latter portion of 1996 to the early portion of 1997.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge

NASA Astrophysics Data System (ADS)

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

Novel high-frequency energy-efficient pulsed-dc generator for capacitively coupled plasma discharge.

PubMed

Mamun, Md Abdullah Al; Furuta, Hiroshi; Hatta, Akimitsu

2018-03-01

The circuit design, assembly, and operating tests of a high-frequency and high-voltage (HV) pulsed dc generator (PDG) for capacitively coupled plasma (CCP) discharge inside a vacuum chamber are reported. For capacitive loads, it is challenging to obtain sharp rectangular pulses with fast rising and falling edges, requiring intense current for quick charging and discharging. The requirement of intense current generally limits the pulse operation frequency. In this study, we present a new type of PDG consisting of a pair of half-resonant converters and a constant current-controller circuit connected with HV solid-state power switches that can deliver almost rectangular high voltage pulses with fast rising and falling edges for CCP discharge. A prototype of the PDG is assembled to modulate from a high-voltage direct current (HVdc) input into a pulsed HVdc output, while following an input pulse signal and a set current level. The pulse rise time and fall time are less than 500 ns and 800 ns, respectively, and the minimum pulse width is 1 µs. The maximum voltage for a negative pulse is 1000 V, and the maximum repetition frequency is 500 kHz. During the pulse on time, the plasma discharge current is controlled steadily at the set value. The half-resonant converters in the PDG perform recovery of the remaining energy from the capacitive load at every termination of pulse discharge. The PDG performed with a high energy efficiency of 85% from the HVdc input to the pulsed dc output at a repetition rate of 1 kHz and with stable plasma operation in various discharge conditions. The results suggest that the developed PDG can be considered to be more efficient for plasma processing by CCP.

The effects of low solar activity upon the cosmic radiation and the interplanetary magnetic field over the past 10,000 years, and implications for the future. (Invited)

NASA Astrophysics Data System (ADS)

McCracken, K. G.; McDonald, F. B.; Beer, J.; Abreu, J.; Steinhilber, F.

2009-12-01

The paleo-cosmic ray records based on the radionuclides 10Be and 14 C show that the Sun has experienced twenty two extended periods of low activity (similar to, or longer than the Maunder Minimum) in the past 10,000 years, and many more periods of reduced activity for 2 or more solar cycles similar to the period 1880-1910. The 10,000 yr record shows that solar activity has exhibited three persistent periodicities that modulate the amplitude of the Hale (11/22 year) cycle. They are the Gleissberg (~85 yr); the de Vries (~208 yr); and the Hallstatt (~2200 yr) periodicities. It is possible that the Sun is entering a somewhat delayed Gleissberg repetition of the 1880-1910 period of reduced activity or a de Vries repetition of the Dalton Minimum of 1800-1820; or a combination of both. The historic record shows that the cosmic ray intensity at sunspot minimum increases substantially during periods of reduced solar activity- during the Dalton minimum it was twice the present-day sunspot minimum intensity at 2GeV/nucleon ; and 10 times greater at 100 MeV/nucleon. The Hale cycle of solar activity continued throughout the Spoerer (1420-1540) and Maunder Minima, and it appears possible that the local interstellar cosmic ray spectrum was occasionally incident on Earth. Using the cosmic ray transport equation to invert the paleo-cosmic ray record shows that the magnetic field was <1nT at Hale minima during the Spoerer Minimum and late in the Maunder Minimum. The Sun was at a minimum of the Hallstatt (2200yr) cycle of activity in the 15th century, and is now on a steadily rising plane of activity. Paleo-cosmic ray evidence suggests that there was a greater production of impulsive solar energetic particle events in the solar cycles of reduced solar activity 1880-1910. Based on these observations, three scenarios for the next several decades will be outlined- (a) a single, deep sunspot minimum followed by an active sun; (b) several cycles of reduced solar activity similar to 1880-1910; and (c) a “Grand Minimum” with one or more 11 year cycles of very low activity similar to the Dalton Minimum.

Solar origins of solar wind properties during the cycle 23 solar minimum and rising phase of cycle 24

PubMed Central

Luhmann, Janet G.; Petrie, Gordon; Riley, Pete

2012-01-01

The solar wind was originally envisioned using a simple dipolar corona/polar coronal hole sources picture, but modern observations and models, together with the recent unusual solar cycle minimum, have demonstrated the limitations of this picture. The solar surface fields in both polar and low-to-mid-latitude active region zones routinely produce coronal magnetic fields and related solar wind sources much more complex than a dipole. This makes low-to-mid latitude coronal holes and their associated streamer boundaries major contributors to what is observed in the ecliptic and affects the Earth. In this paper we use magnetogram-based coronal field models to describe the conditions that prevailed in the corona from the decline of cycle 23 into the rising phase of cycle 24. The results emphasize the need for adopting new views of what is ‘typical’ solar wind, even when the Sun is relatively inactive. PMID:25685422

Coral colonisation of a shallow reef flat in response to rising sea level: quantification from 35 years of remote sensing data at Heron Island, Australia

NASA Astrophysics Data System (ADS)

Scopélitis, J.; Andréfouët, S.; Phinn, S.; Done, T.; Chabanet, P.

2011-12-01

Observations made on Heron Island reef flat during the 1970s-1990s highlighted the importance of rapid change in hydrodynamics and accommodation space for coral development. Between the 1940s and the 1990s, the minimum reef-flat top water level varied by some tens of centimetres, successively down then up, in rapid response to local engineering works. Coral growth followed sea-level variations and was quantified here for several coral communities using horizontal two-dimensional above water remotely sensed observations. This required seven high spatial resolution aerial photographs and Quickbird satellite images spanning 35 years: 1972, 1979, 1990, 1992, 2002, 2006 and 2007. The coral growth dynamics followed four regimes corresponding to artificially induced changes in sea levels: 1972-1979 (lowest growth rate): no detectable coral development, due to high tidal currents and minimum mean low-tide water level; 1979-1991 (higher growth rate): horizontal coral development promoted by calmer hydrodynamic conditions; 1991-2001(lower growth rate): vertical coral development, induced by increased local sea level by ~12 cm due to construction of new bund walls; 2001-2007 (highest growth rate): horizontal coral development after that vertical growth had become limited by sea level. This unique time-series displays a succession of ecological stage comprising a `catch-up' dynamic in response to a rapid local sea-level rise in spite of the occurrences of the most severe bleaching events on record (1998, 2002) and the decreasing calcification rates reported in massive corals in the northern part of the Great Barrier Reef.

Sunspot Time Series: Passive and Active Intervals

NASA Astrophysics Data System (ADS)

Zięba, S.; Nieckarz, Z.

2014-07-01

Solar activity slowly and irregularly decreases from the first spotless day (FSD) in the declining phase of the old sunspot cycle and systematically, but also in an irregular way, increases to the new cycle maximum after the last spotless day (LSD). The time interval between the first and the last spotless day can be called the passive interval (PI), while the time interval from the last spotless day to the first one after the new cycle maximum is the related active interval (AI). Minima of solar cycles are inside PIs, while maxima are inside AIs. In this article, we study the properties of passive and active intervals to determine the relation between them. We have found that some properties of PIs, and related AIs, differ significantly between two group of solar cycles; this has allowed us to classify Cycles 8 - 15 as passive cycles, and Cycles 17 - 23 as active ones. We conclude that the solar activity in the PI declining phase (a descending phase of the previous cycle) determines the strength of the approaching maximum in the case of active cycles, while the activity of the PI rising phase (a phase of the ongoing cycle early growth) determines the strength of passive cycles. This can have implications for solar dynamo models. Our approach indicates the important role of solar activity during the declining and the rising phases of the solar-cycle minimum.

Nanoscale Mo- MoO3 Entrapped in Engineering Thermoplastic: Inorganic Pathway to Bactericidal and Fungicidal Action.

PubMed

Qureshi, Nilam; Chaudhari, Ravindra; Mane, Pramod; Shinde, Manish; Jadakar, Sandesh; Rane, Sunit; Kale, Bharat; Bhalerao, Anand; Amalnerkar, Dinesh

2016-04-01

In our contemporary endeavor, metallic molybdenum (Mo) and semiconducting molybdenum trioxide (MoO3) nanostructures have been simultaneously generated via solid state reaction between molybdenum (III) chloride (MoCl3) and polyphenylene sulfide (PPS) at 285 (°)C in unimolar ratio for different time durations, namely, 6 h, 24 h, and 48 h. The resultant nanocomposites (NCs) revealed formation of predominantly metallic Mo for all the samples. However, MoO3 gradually gained prominent position as secondary phase with rise in reaction time. The present study was intended to investigate the antibacterial potential of metal-metal oxide-polymer NCs, i.e., Mo- MoO3-PPS against microorganisms, viz., Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, and Aspergillus fumigatus. The antibacterial activity of the NCs was evaluated by agar well diffusion investigation. Maximum sensitivity concentrations of NCs were determined by finding out minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC). Moreover, the NCs prepared at reaction time of 48 h exhibited best MBC values and were tested with time kill assay which revealed that the growth of S. aureus was substantially inhibited by Mo- MoO3-PPS NCs. This synchronized formation of Mo- MoO3 nanostructures in an engineering thermoplastic may have potential antimicrobial applications in biomedical devices and components. Prima facie results on antifungal activity are indicative of the fact that these materials can show anti-cancer behavior.

Resolving the Cygnus X-3 iron K line

NASA Technical Reports Server (NTRS)

Kitamoto, Shunji; Kawashima, Kenji; Negoro, Hitoshi; Miyamoto, Sigenori; White, N. E.; Nagase, Fumiaki

1994-01-01

An Advanced Satellite for Cosmology and Astrophysics (ASCA) observation of Cygnus X-3 on 1993 June 11, in its X-ray high intensity state, has for the first time resolved the broad iron K line emission into three components: a He-like line at 6.67 +/- 0.01 keV, a H-like line at 6.96 +/- 0.02 keV, and a neutral line at 6.37 +/- 0.03 keV. The line intensities of the 6.67 keV and 6.96 keV lines are modulated with the 4.8 hr orbital period and are maximum when the continuum intensity is minimum. There is a sharp minimum of the line intensity on the rising phase of the continuum intensity. An iron absorption edge is observed at 7.19 +/- 0.02 keV. The optical depth of the absorption edge varies from 0.3 to 0.5 and is in anti-phase with the overall X-ray continuum modulation. The observed complexity of the iron K line region is greater than that had been assumed in previous spectral modeling based on observations with lower resolution detectors.

Grand minima of solar activity and sociodynamics of culture

NASA Astrophysics Data System (ADS)

Vladimirsky, B. M.

2012-12-01

Indices of creative productivity introduced by C. Murrey were used to verify S. Ertel's conclusion about a global increase in creative productivity during the prolonged minimum of solar activity in 1640-1710. It was found that these indices for mathematicians, philosophers, and scientists increase in the Maunder era by factor of 1.6 in comparison with intervals of the same length before and after the minimum. A similar effect was obtained for mathematicians and philosophers for five earlier equitype minima in total (an increase by a factor of 1.9). The regularity that is revealed is confirmed by the fact that the most important achievements of high-ranking mathematicians and philosophers during the whole time period (2300 years) considered in this study fall on epochs of reduced levels of solar activity. The rise in the probability of the generation of rational ideas during grand minima is reflected also in the fact that they precede the appearance of written language and farming. Ultra-low-frequency electromagnetic fields appear to serve as a physical agent stimulating the activity of the brain's left hemisphere during the epochs of minima.

Pieces of the ancient lunar crust - Ages and composition of clasts in consortium breccia 67915

NASA Technical Reports Server (NTRS)

Marti, K.; Jost, D. T.; Aeschlimann, U.; Eberhardt, P.; Geiss, J.; Groegler, N.; Laul, J. C.; Ma, M.-S.; Schmitt, R. A.; Taylor, G. J.

1983-01-01

The composition and chronology of clasts representing three minor lithologies in consortium breccia 67915 are discussed. The lithologies studied are: sodic ferrogabbro, pristine troctolitic anorthosite (67915,26), and granulitic troctolitic anorthosite (67915,67). These lithologies were presumed to represent samples of the ancient lunar crust. The pristine troctolitic anorthosite, a typical member of the pristine anorthosite suite, contains little or no trapped liquid consistent with its two-phase mineralogy. The plagioclase separates have Ar-39-Ar-40 plateau ages of 4.10 + or - 0.06 b.y., and a final rise in the age pattern may represent a 'memory' of the earlier evolution. The granulitic troctolitic anorthosite, which has 13 times larger REE abundances, displays a continuous rise of the Ar-40/Ar-39 ratio. The last 25 percent of the Ar-39 release data establish a minimum age of over 3.5 b.y., but the Pu-244/Nd chronology suggests an age of about 4.3 b.y. The sodic ferrogabbro samples, which appear to be members of the Mg-gabbronorite group of pristine rocks, show large Ar losses but indicate plateaus in the low-temperature data, suggesting a metamorphic event more recently than 260 m.y. ago, a time that is consistent with the North Ray impact event 50 m.y. ago.

A time-frequency classifier for human gait recognition

NASA Astrophysics Data System (ADS)

Mobasseri, Bijan G.; Amin, Moeness G.

2009-05-01

Radar has established itself as an effective all-weather, day or night sensor. Radar signals can penetrate walls and provide information on moving targets. Recently, radar has been used as an effective biometric sensor for classification of gait. The return from a coherent radar system contains a frequency offset in the carrier frequency, known as the Doppler Effect. The movements of arms and legs give rise to micro Doppler which can be clearly detailed in the time-frequency domain using traditional or modern time-frequency signal representation. In this paper we propose a gait classifier based on subspace learning using principal components analysis(PCA). The training set consists of feature vectors defined as either time or frequency snapshots taken from the spectrogram of radar backscatter. We show that gait signature is captured effectively in feature vectors. Feature vectors are then used in training a minimum distance classifier based on Mahalanobis distance metric. Results show that gait classification with high accuracy and short observation window is achievable using the proposed classifier.

Care homes may close due to cost of national living wage.

PubMed

Sprinks, Jennifer

2016-08-01

In April this year, a compulsory national living wage (NLW) for people over the age of 25 was introduced across the UK. The NLW increases minimum hourly pay from £6.70 to £7.20, a figure that is due to rise to £9 by 2020.

Future trends which will influence waste disposal.

PubMed Central

Wolman, A

1978-01-01

The disposal and management of solid wastes are ancient problems. The evolution of practices naturally changed as populations grew and sites for disposal became less acceptable. The central search was for easy disposal at minimum costs. The methods changed from indiscriminate dumping to sanitary landfill, feeding to swine, reduction, incineration, and various forms of re-use and recycling. Virtually all procedures have disabilities and rising costs. Many methods once abandoned are being rediscovered. Promises for so-called innovations outstrip accomplishments. Markets for salvage vary widely or disappear completely. The search for conserving materials and energy at minimum cost must go on forever. PMID:570105

Broad-Band Pump-Probe Spectroscopy Quantifies Ultrafast Solvation Dynamics of Proteins and Molecules.

PubMed

Jumper, Chanelle C; Arpin, Paul C; Turner, Daniel B; McClure, Scott D; Rafiq, Shahnawaz; Dean, Jacob C; Cina, Jeffrey A; Kovac, Philip A; Mirkovic, Tihana; Scholes, Gregory D

2016-11-17

In this work, we demonstrate the use of broad-band pump-probe spectroscopy to measure femtosecond solvation dynamics. We report studies of a rhodamine dye in methanol and cryptophyte algae light-harvesting proteins in aqueous suspension. Broad-band impulsive excitation generates a vibrational wavepacket that oscillates on the excited-state potential energy surface, destructively interfering with itself at the minimum of the surface. This destructive interference gives rise to a node at a certain probe wavelength that varies with time. This reveals the Gibbs free-energy changes of the excited-state potential energy surface, which equates to the solvation time correlation function. This method captures the inertial solvent response of water (∼40 fs) and the bimodal inertial response of methanol (∼40 and ∼150 fs) and reveals how protein-buried chromophores are sensitive to the solvent dynamics inside and outside of the protein environment.

City ventilation of Hong Kong at no-wind conditions

NASA Astrophysics Data System (ADS)

Yang, Lina; Li, Yuguo

We hypothesize that city ventilation due to both thermally-driven mountain slope flows and building surface flows is important in removing ambient airborne pollutants in the high-rise dense city Hong Kong at no-wind conditions. Both spatial and temporal urban surface temperature profiles are an important boundary condition for studying city ventilation by thermal buoyancy. Field measurements were carried out to investigate the diurnal thermal behavior of urban surfaces (mountain slopes, and building exterior walls and roofs) in Hong Kong by using the infrared thermography. The maximum urban surface temperature was measured in the early noon hours (14:00-15:00 h) and the minimum temperature was observed just before sunrise (5:00 h). The vertical surface temperature of the building exterior wall was found to increase with height at daytime and the opposite occurred at nighttime. The solar radiation and the physical properties of the various urban surfaces were found to be important factors affecting the surface thermal behaviors. The temperature difference between the measured maximum and minimum surface temperatures of the four selected exterior walls can be at the highest of 16.7 °C in the early afternoon hours (15:00 h). Based on the measured surface temperatures, the ventilation rate due to thermal buoyancy-induced wall surface flows of buildings and mountain slope winds were estimated through an integral analysis of the natural convection flow over a flat surface. At no-wind conditions, the total air change rate by the building wall flows (2-4 ACH) was found to be 2-4 times greater than that by the slope flows due to mountain surface (1 ACH) due to larger building exterior surface areas and temperature differences with surrounding air. The results provide useful insights into the ventilation of a high-rise dense city at no-wind conditions.

Seagrass habitat metabolism increases short-term extremes and long-term offset of CO2 under future ocean acidification.

PubMed

Pacella, Stephen R; Brown, Cheryl A; Waldbusser, George G; Labiosa, Rochelle G; Hales, Burke

2018-04-10

The role of rising atmospheric CO 2 in modulating estuarine carbonate system dynamics remains poorly characterized, likely due to myriad processes driving the complex chemistry in these habitats. We reconstructed the full carbonate system of an estuarine seagrass habitat for a summer period of 2.5 months utilizing a combination of time-series observations and mechanistic modeling, and quantified the roles of aerobic metabolism, mixing, and gas exchange in the observed dynamics. The anthropogenic CO 2 burden in the habitat was estimated for the years 1765-2100 to quantify changes in observed high-frequency carbonate chemistry dynamics. The addition of anthropogenic CO 2 alters the thermodynamic buffer factors (e.g., the Revelle factor) of the carbonate system, decreasing the seagrass habitat's ability to buffer natural carbonate system fluctuations. As a result, the most harmful carbonate system indices for many estuarine organisms [minimum pH T , minimum Ω arag , and maximum pCO 2(s.w.) ] change up to 1.8×, 2.3×, and 1.5× more rapidly than the medians for each parameter, respectively. In this system, the relative benefits of the seagrass habitat in locally mitigating ocean acidification increase with the higher atmospheric CO 2 levels predicted toward 2100. Presently, however, these mitigating effects are mixed due to intense diel cycling of CO 2 driven by aerobic metabolism. This study provides estimates of how high-frequency pH T , Ω arag , and pCO 2(s.w.) dynamics are altered by rising atmospheric CO 2 in an estuarine habitat, and highlights nonlinear responses of coastal carbonate parameters to ocean acidification relevant for water quality management.

Seagrass habitat metabolism increases short-term extremes and long-term offset of CO2 under future ocean acidification

NASA Astrophysics Data System (ADS)

Pacella, Stephen R.; Brown, Cheryl A.; Waldbusser, George G.; Labiosa, Rochelle G.; Hales, Burke

2018-04-01

The role of rising atmospheric CO2 in modulating estuarine carbonate system dynamics remains poorly characterized, likely due to myriad processes driving the complex chemistry in these habitats. We reconstructed the full carbonate system of an estuarine seagrass habitat for a summer period of 2.5 months utilizing a combination of time-series observations and mechanistic modeling, and quantified the roles of aerobic metabolism, mixing, and gas exchange in the observed dynamics. The anthropogenic CO2 burden in the habitat was estimated for the years 1765–2100 to quantify changes in observed high-frequency carbonate chemistry dynamics. The addition of anthropogenic CO2 alters the thermodynamic buffer factors (e.g., the Revelle factor) of the carbonate system, decreasing the seagrass habitat’s ability to buffer natural carbonate system fluctuations. As a result, the most harmful carbonate system indices for many estuarine organisms [minimum pHT, minimum Ωarag, and maximum pCO2(s.w.)] change up to 1.8×, 2.3×, and 1.5× more rapidly than the medians for each parameter, respectively. In this system, the relative benefits of the seagrass habitat in locally mitigating ocean acidification increase with the higher atmospheric CO2 levels predicted toward 2100. Presently, however, these mitigating effects are mixed due to intense diel cycling of CO2 driven by aerobic metabolism. This study provides estimates of how high-frequency pHT, Ωarag, and pCO2(s.w.) dynamics are altered by rising atmospheric CO2 in an estuarine habitat, and highlights nonlinear responses of coastal carbonate parameters to ocean acidification relevant for water quality management.

Spatial variations of sea level along the coast of Thailand: Impacts of extreme land subsidence, earthquakes and the seasonal monsoon

NASA Astrophysics Data System (ADS)

Saramul, Suriyan; Ezer, Tal

2014-11-01

The study addresses two important issues associated with sea level along the coasts of Thailand: first, the fast sea level rise and its spatial variation, and second, the monsoonal-driven seasonal variations in sea level. Tide gauge data that are more extensive than in past studies were obtained from several different local and global sources, and relative sea level rise (RSLR) rates were obtained from two different methods, linear regressions and non-linear Empirical Mode Decomposition/Hilbert-Huang Transform (EMD/HHT) analysis. The results show extremely large spatial variations in RSLR, with rates varying from ~ 1 mm y-1 to ~ 20 mm y-1; the maximum RSLR is found in the upper Gulf of Thailand (GOT) near Bangkok, where local land subsidence due to groundwater extraction dominates the trend. Furthermore, there are indications that RSLR rates increased significantly in all locations after the 2004 Sumatra-Andaman Earthquake and the Indian Ocean tsunami that followed, so that recent RSLR rates seem to have less spatial differences than in the past, but with high rates of ~ 20-30 mm y-1 almost everywhere. The seasonal sea level cycle was found to be very different between stations in the GOT, which have minimum sea level in June-July, and stations in the Andaman Sea, which have minimum sea level in February. The seasonal sea-level variations in the GOT are driven mostly by large-scale wind-driven set-up/set-down processes associated with the seasonal monsoon and have amplitudes about ten times larger than either typical steric changes at those latitudes or astronomical annual tides.

Persister cells, the biofilm matrix and tolerance to metal cations in biofilm and planktonic Pseudomonas aeruginosa.

PubMed

Harrison, Joe J; Turner, Raymond J; Ceri, Howard

2005-07-01

In this study, we examined Pseudomonas aeruginosa ATCC 27853 biofilm and planktonic cell susceptibility to metal cations. The minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC) required to eradicate 100% of the planktonic population (MBC 100), and the minimum biofilm eradication concentration (MBEC) were determined using the MBEC trade mark-high throughput assay. Six metals - Co(2+), Ni(2+), Cu(2+), Zn(2+), Al(3+) and Pb(2+)- were each tested at 2, 4, 6, 8, 10 and 27 h of exposure to biofilm and planktonic cultures grown in rich or minimal media. With 2 or 4 h of exposure, biofilms were approximately 2-25 times more tolerant to killing by metal cations than the corresponding planktonic cultures. However, by 27 h of exposure, biofilm and planktonic bacteria were eradicated at approximately the same concentration in every instance. Viable cell counts evaluated at 2 and 27 h of exposure revealed that at high concentrations, most of the metals assayed had killed greater than 99.9% of biofilm and planktonic cell populations. The surviving cells were propogated in vitro and gave rise to biofilm and planktonic cultures with normal sensitivity to metals. Further, retention of copper by the biofilm matrix was investigated using the chelator sodium diethlydithiocarbamate. Formation of visible brown metal-chelates in biofilms treated with Cu(2+) suggests that the biofilm matrix may coordinate and sequester metal cations from the aqueous surroundings. Overall, our data suggest that both metal sequestration in the biofilm matrix and the presence of a small population of 'persister' cells may be contributing factors in the time-dependent tolerance of both planktonic cells and biofilms to high concentrations of metal cations.

Investigating the effects of an oral fructose challenge on hepatic ATP reserves in healthy volunteers: A (31)P MRS study.

PubMed

Bawden, S J; Stephenson, M C; Ciampi, E; Hunter, K; Marciani, L; Macdonald, I A; Aithal, G P; Morris, P G; Gowland, P A

2016-06-01

Impaired homeostasis of hepatic ATP has been associated with NAFLD. An intravenous fructose infusion has been shown to be an effective challenge to monitor the depletion and subsequent recovery of hepatic ATP reserves using (31)P MRS. The purpose of this study was to evaluate the effects of an oral rather than intravenous fructose challenge on hepatic ATP reserves in healthy subjects. Self-reported healthy males were recruited. Following an overnight fast, baseline liver glycogen and lipid levels were measured using Magnetic Resonance Spectroscopy (MRS). Immediately after consuming a 500 ml 75 g fructose drink (1275 kJ) subjects were scanned continuously for 90 min to acquire dynamic (31)P MRS measurements of liver ATP reserves. A significant effect on ATP reserves was observed across the time course (P < 0.05). Mean ATP levels reached a minimum at 50 min which was markedly lower than baseline (80 ± 17% baseline, P < 0.05). Subsequently, mean values tended to rise but did not reach statistical significance above minimum. The time to minimum ATP levels across subjects was negatively correlated with BMI (R(2) = 0.74, P < 0.005). Rates of ATP recovery were not significantly correlated with BMI or liver fat levels, but were negatively correlated with baseline glycogen levels (R(2) = 0.7, P < 0.05). Depletion of ATP reserves can be measured non-invasively following an oral fructose challenge using (31)P MRS. BMI is the best predictor of postprandial ATP homeostasis following fructose consumption. Copyright © 2015 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

10 CFR 420.15 - Minimum criteria for required program activities for plans.

Code of Federal Regulations, 2011 CFR

2011-01-01

... leased by the United States), above a certain size, as determined by the State; (3) For new public... political subdivisions. (d) Mandatory thermal efficiency standards for new and renovated buildings shall— (1... design and equipment selection; (3) For all new commercial and multifamily high-rise buildings, be no...

Overview of Nepal's energy sources and environment

NASA Astrophysics Data System (ADS)

Sharma, C. K.

In the Kathmandu Valley, Nepal faces environmental problems of most industrialized countries whereas it has problems similar to the least developed countries, in the hills. Types and quantity of energy use have a close link with the environmental degradation in Nepal Himalaya. Over dependence on the forest to meet the energy demand in the hills has aggravated the environmental problems. Lack of forest cover on the hills, the intense monsoon rain, the fragile geology and steep terrain are contributing to the acceleration of landslides, soil erosion and temperature rise. The rise of average minimum temperature is causing glaciers to retreat and thereby the development of large bodies of glacial lake. Glacial lake outbursts of 1981 in Kodari and of 1985 in Namche bazar area caused extensive damage on infrastructures down stream. Heavy use of commercial fuel (hydrocarbons) in the bowl shaped Kathmandu valley is causing air and water pollution and an increase in the average minimum temperature. Extensive development of hydropower, biogas plants and massive reforestation on naked hills and efficient use of imported hydrocarbons are the solution to existing energy and environmental problems.

Standard Galactic Field RR Lyrae. I. Optical to Mid-infrared Phased Photometry

NASA Astrophysics Data System (ADS)

Monson, Andrew J.; Beaton, Rachael L.; Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Rich, Jeffrey A.; Seibert, Mark; Kollmeier, Juna A.; Clementini, Gisella

2017-03-01

We present a multi-wavelength compilation of new and previously published photometry for 55 Galactic field RR Lyrae variables. Individual studies, spanning a time baseline of up to 30 years, are self-consistently phased to produce light curves in 10 photometric bands covering the wavelength range from 0.4 to 4.5 microns. Data smoothing via the GLOESS technique is described and applied to generate high-fidelity light curves, from which mean magnitudes, amplitudes, rise times, and times of minimum and maximum light are derived. 60,000 observations were acquired using the new robotic Three-hundred MilliMeter Telescope (TMMT), which was first deployed at the Carnegie Observatories in Pasadena, CA, and is now permanently installed and operating at Las Campanas Observatory in Chile. We provide a full description of the TMMT hardware, software, and data reduction pipeline. Archival photometry contributed approximately 31,000 observations. Photometric data are given in the standard Johnson UBV, Kron-Cousins {R}C{I}C, 2MASS JHK, and Spitzer [3.6] and [4.5] bandpasses.

A Comparison of Several Methods of Measuring Ignition Lag in a Compression-ignition Engine

NASA Technical Reports Server (NTRS)

Spanogle, J A

1934-01-01

The ignition lag of a fuel oil in the combustion chamber of a high speed compression-ignition engine was measured by three different methods. The start of injection of the fuel as observed with a Stoborama was taken as the start of the period of ignition lag in all cases. The end of the period of ignition lag was determined by observation of the appearance of incandescence in the combustion chamber, by inspection of a pressure-time card for evidence of pressure rise, and by analysis of the indicator card for evidence of the combustion of a small but definite quantity of fuel. A comparison of the values for ignition lags obtained by these three methods indicates that the appearance of incandescence is later than other evidences of the start of combustion, that visual inspection of a pressure-time diagram gives consistent and usable values with a minimum requirement of time and/or apparatus, and that analysis of the indicator card is not worth while for ignition lag alone.

A dynamic processes study of PM retention by trees under different wind conditions.

PubMed

Xie, Changkun; Kan, Liyan; Guo, Jiankang; Jin, Sijia; Li, Zhigang; Chen, Dan; Li, Xin; Che, Shengquan

2018-02-01

Particulate matter (PM) is one of the most serious environmental problems, exacerbating respiratory and vascular illnesses. Plants have the ability to reduce non-point source PM pollution through retention on leaves and branches. Studies of the dynamic processes of PM retention by plants and the mechanisms influencing this process will help to improve the efficiency of urban greening for PM reduction. We examined dynamic processes of PM retention and the major factors influencing PM retention by six trees with different branch structure characteristics in wind tunnel experiments at three different wind speeds. The results showed that the changes of PM numbers retained by plant leaves over time were complex dynamic processes for which maximum values could exceed minimum values by over 10 times. The average value of PM measured in multiple periods and situations can be considered a reliable indicator of the ability of the plant to retain PM. The dynamic processes were similar for PM 10 and PM 2.5 . They could be clustered into three groups simulated by continually-rising, inverse U-shaped, and U-shaped polynomial functions, respectively. The processes were the synthetic effect of characteristics such as species, wind speed, period of exposure and their interactions. Continually-rising functions always explained PM retention in species with extremely complex branch structure. Inverse U-shaped processes explained PM retention in species with relatively simple branch structure and gentle wind. The U-shaped processes mainly explained PM retention at high wind speeds and in species with a relatively simple crown. These results indicate that using plants with complex crowns in urban greening and decreasing wind speed in plant communities increases the chance of continually-rising or inverse U-shaped relationships, which have a positive effect in reducing PM pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Corrigendum: Bounding sea level projections within the framework of the possibility theory Environ. Res. Lett. (2017 12 014012)

NASA Astrophysics Data System (ADS)

Le Cozannet, Gonéri; Manceau, Jean-Charles; Rohmer, Jeremy

2017-10-01

Figures 3 and 4 of the article ‘Bounding probabilistic sea-level projections within the framework of the possibility theory’ display a minimum value for sea level rise of 15 cm by 2100 with respect to the 1986-2005 mean for the RCP 8.5. The value of 15 cm is consistent with sea level rise rates dropping back to velocities observed during the 20th century according to recent studies, but not to the current sea level rise velocity of 3.4 mm yr-1, as incorrectly stated in the article. This error has no impact on the rest of the article, including its arguments and conclusions, but it is potentially confusing for scientists willing to reproduce the left side of figures 3 and 4. We apologise for any inconvenience caused.

Design optimization and probabilistic analysis of a hydrodynamic journal bearing

NASA Technical Reports Server (NTRS)

Liniecki, Alexander G.

1990-01-01

A nonlinear constrained optimization of a hydrodynamic bearing was performed yielding three main variables: radial clearance, bearing length to diameter ratio, and lubricating oil viscosity. As an objective function a combined model of temperature rise and oil supply has been adopted. The optimized model of the bearing has been simulated for population of 1000 cases using Monte Carlo statistical method. It appeared that the so called 'optimal solution' generated more than 50 percent of failed bearings, because their minimum oil film thickness violated stipulated minimum constraint value. As a remedy change of oil viscosity is suggested after several sensitivities of variables have been investigated.

Anticipating Cycle 24 Minimum and its Consequences: An Update

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.

2008-01-01

This Technical Publication updates estimates for cycle 24 minimum and discusses consequences associated with cycle 23 being a longer than average period cycle and cycle 24 having parametric minimum values smaller (or larger for the case of spotless days) than long term medians. Through December 2007, cycle 23 has persisted 140 mo from its 12-mo moving average (12-mma) minimum monthly mean sunspot number occurrence date (May 1996). Longer than average period cycles of the modern era (since cycle 12) have minimum-to-minimum periods of about 139.0+/-6.3 mo (the 90-percent prediction interval), inferring that cycle 24 s minimum monthly mean sunspot number should be expected before July 2008. The major consequence of this is that, unless cycle 24 is a statistical outlier (like cycle 21), its maximum amplitude (RM) likely will be smaller than previously forecast. If, however, in the course of its rise cycle 24 s 12-mma of the weighted mean latitude (L) of spot groups exceeds 24 deg, then one expects RM >131, and if its 12-mma of highest latitude (H) spot groups exceeds 38 deg, then one expects RM >127. High-latitude new cycle spot groups, while first reported in January 2008, have not, as yet, become the dominant form of spot groups. Minimum values in L and H were observed in mid 2007 and values are now slowly increasing, a precondition for the imminent onset of the new sunspot cycle.

Thermal waves or beam heating in the 1980, November 5 flare

NASA Technical Reports Server (NTRS)

Smith, Dean F.

1986-01-01

Observations of the temporal evolution of loop BC in soft X rays in the November 5, 1980 flare are reviewed. Calculations are performed to model this evolution. The most consistent interpretation involving a minimum account of energy is the following. Thermal heating near B gives rise to a conduction front which moves out along the loop uninhibited for about 27 s. Beam heating near C gives rise to a second conduction front which moves in the opposite direction and prevents any energy reaching C by thermal conduction from B. Thus both thermal waves and beam heating are required to explain the observed evolution.

Efforts to Prevent Concussions Target Schools

ERIC Educational Resources Information Center

Samuels, Christina A.

2010-01-01

The number of sports-related concussions reported by young athletes is on the rise, prompting awareness campaigns from athletic and medical groups, as well as proposed federal legislation to set minimum standards for concussion management in public schools. Concussions are caused by a jolt to the body or a blow to the head that causes the head to…

Extreme Family Poverty Rises in the Midst of a Strong Economy. Family Review.

ERIC Educational Resources Information Center

Lindjord, Denise

2000-01-01

Discusses the sudden increase of families with incomes below 50 percent of the poverty line, noting particularly the impact on children. Notes a direct link between increased family poverty and the decreasing protective role of cash welfare and food stamp benefits. Describes federal proposals to increase minimum wage and cut taxes; makes…

Predicting the Size and Timing of Sunspot Maximum for Cycle 24

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2010-01-01

For cycle 24, the minimum value of the 12-month moving average (12-mma) of the AA-geomagnetic index in the vicinity of sunspot minimum (AAm) appears to have occurred in September 2009, measuring about 8.4 nT and following sunspot minimum by 9 months. This is the lowest value of AAm ever recorded, falling below that of 8.9 nT, previously attributed to cycle 14, which also is the smallest maximum amplitude (RM) cycle of the modern era (RM = 64.2). Based on the method of Ohl (the preferential association between RM and AAm for an ongoing cycle), one expects cycle 24 to have RM = 55+/-17 (the +/-1 - sigma prediction interval). Instead, using a variation of Ohl's method, one based on using 2-cycle moving averages (2-cma), one expects cycle 23's 2-cma of RM to be about 115.5+/-8.7 (the +/-1 - sigma prediction interval), inferring an RM of about 62+/-35 for cycle 24. Hence, it seems clear that cycle 24 will be smaller in size than was seen in cycle 23 (RM = 120.8) and, likely, will be comparable in size to that of cycle 14. From the Waldmeier effect (the preferential association between the ascent duration (ASC) and RM for an ongoing cycle), one expects cycle 24 to be a slow-rising cycle (ASC > or equal to 48 months), having RM occurrence after December 2012, unless it turns out to be a statistical outlier.

Age validation of quillback rockfish (Sebastes maliger) using bomb radiocarbon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kerr, L A; Andrews, A H; Munk, K

2005-01-05

Rockfishes (Sebastes spp.) support one of the most economically important fisheries of the Pacific Northwest and it is essential for sustainable management that age estimation procedures be validated for these species. Atmospheric testing of thermonuclear devices during the 1950s and 1960s created a global radiocarbon ({sup 14}C) signal in the ocean environment that scientists have identified as a useful tracer and chronological marker in natural systems. In this study, we first demonstrated that fewer samples are necessary for age validation using the bomb-generated {sup 14}C signal by emphasizing the utility of the time-specific marker created by the initial rise ofmore » bomb-{sup 14}C. Second, the bomb-generated {sup 14}C signal retained in fish otoliths was used to validate the age and age estimation methodology of the quillback rockfish (Sebastes maliger) in the waters of southeast Alaska. Radiocarbon values from the first year's growth of quillback rockfish otoliths were plotted against estimated birth year producing a {sup 14}C time series spanning 1950 to 1985. The initial rise of bomb-{sup 14}C from pre-bomb levels ({approx} -90 {per_thousand}) occurred in 1959 {+-} 1 year and {sup 14}C levels rose relatively rapidly to peak {Delta}{sup 14}C values in 1967 (+105.4 {per_thousand}), with a subsequent declining trend through the end of the record in 1985 (+15.4 {per_thousand}). The agreement between the year of initial rise of {sup 14}C levels from the quillback rockfish record and the chronometer determined for the waters of southeast Alaska from yelloweye rockfish (S. ruberrimus) otoliths validated the ageing methodology for the quillback rockfish. The concordance of the entire quillback rockfish {sup 14}C record with the yelloweye rockfish time series demonstrated the effectiveness of this age validation technique, confirmed the longevity of the quillback rockfish up to a minimum of 43 years, and strongly supports higher age estimates of up to 90 years.« less

Predicting water table response to rainfall events, central Florida.

PubMed

van Gaalen, J F; Kruse, S; Lafrenz, W B; Burroughs, S M

2013-01-01

A rise in water table in response to a rainfall event is a complex function of permeability, specific yield, antecedent soil-water conditions, water table level, evapotranspiration, vegetation, lateral groundwater flow, and rainfall volume and intensity. Predictions of water table response, however, commonly assume a linear relationship between response and rainfall based on cumulative analysis of water level and rainfall logs. By identifying individual rainfall events and responses, we examine how the response/rainfall ratio varies as a function of antecedent water table level (stage) and rainfall event size. For wells in wetlands and uplands in central Florida, incorporating stage and event size improves forecasting of water table rise by more than 30%, based on 10 years of data. At the 11 sites studied, the water table is generally least responsive to rainfall at smallest and largest rainfall event sizes and at lower stages. At most sites the minimum amount of rainfall required to induce a rise in water table is fairly uniform when the water table is within 50 to 100 cm of land surface. Below this depth, the minimum typically gradually increases with depth. These observations can be qualitatively explained by unsaturated zone flow processes. Overall, response/rainfall ratios are higher in wetlands and lower in uplands, presumably reflecting lower specific yields and greater lateral influx in wetland sites. Pronounced depth variations in rainfall/response ratios appear to correlate with soil layer boundaries, where corroborating data are available. © 2012, The Author(s). Groundwater © 2012, National Ground Water Association.

Eddy-driven sediment transport in the Argentine Basin: Is the height of the Zapiola Rise hydrodynamically controlled?

DOE PAGES

Weijer, Wilbert; Maltrud, Mathew E.; Homoky, William B.; ...

2015-03-27

In this study, we address the question whether eddy-driven transports in the Argentine Basin can be held responsible for enhanced sediment accumulation over the Zapiola Rise, hence accounting for the existence and growth of this sediment drift. To address this question, we perform a 6 year simulation with a strongly eddying ocean model. We release two passive tracers, with settling velocities that are consistent with silt and clay size particles. Our experiments show contrasting behavior between the silt fraction and the lighter clay. Due to its larger settling velocity, the silt fraction reaches a quasisteady state within a few years,more » with abyssal sedimentation rates that match net input. In contrast, clay settles only slowly, and its distribution is heavily stratified, being transported mainly along isopycnals. Yet, both size classes display a significant and persistent concentration minimum over the Zapiola Rise. We show that the Zapiola Anticyclone, a strong eddy-driven vortex that circulates around the Zapiola Rise, is a barrier to sediment transport, and hence prevents significant accumulation of sediments on the Rise. We conclude that sediment transport by the turbulent circulation in the Argentine Basin alone cannot account for the preferred sediment accumulation over the Rise. We speculate that resuspension is a critical process in the formation and maintenance of the Zapiola Rise.« less

Influence of the optical fiber type on the performances of fiber-optics current sensor dedicated to plasma current measurement in ITER.

PubMed

Aerssens, Matthieu; Descamps, Frédéric; Gusarov, Andrei; Mégret, Patrice; Moreau, Philippe; Wuilpart, Marc

2015-07-01

In this paper, we compare, by means of simulations using the Jones formalism, the performances of several optical fiber types (low birefringence and spun fibers) for the measurement of plasma current in international thermonuclear experimental reactor (ITER). The main results presented in this paper concern the minimum value of the ratio between the beat length and the spun period, which allows meeting the ITER current measurement specifications. Assuming a high-birefringence spun fiber with a beat length of 3 mm, we demonstrate that the minimum ratio between the beat length and the spun period is 4.4 when considering a 28 m long sensing fiber surrounding the vacuum vessel. This minimum ratio rises to 10.14 when a 100 m long lead fiber connecting the interrogating system to the sensing fiber is taken into account.

Two-parameter model of total solar irradiance variation over the solar cycle

NASA Technical Reports Server (NTRS)

Pap, Judit M.; Willson, Richard C.; Donnelly, Richard F.

1991-01-01

Total solar irradiance measured by the SMM/ACRIM radiometer is modelled from the Photometric Sunspot Index and the Mg II core-to-wing ratio with multiple regression analysis. Considering that the formation of the Mg II line is very similar to that of the Ca II K line, the Mg II core-to-wing ratio, measured by the Nimbus-7 and NOAA9 satellites, is used as a proxy for the bright magnetic elements, including faculae and the magnetic network. It is shown that the relationship between the variations in total solar irradiance and the above solar activity indices depends upon the phase of the solar cycle. Thus, a better fit between total irradiance and its model estimates can be achieved if the irradiance models are calculated for the declining portion and minimum of solar cycle 21, and the rising portion of solar cycle 22, respectively. There is an indication that during the rising portion of solar cycle 22, similar to the maximum time of solar cycle 21, the modelled total irradiance values underestimate the measured values. This suggests that there is an asymmetry in the long-term total irradiance variability.

Minimum and Maximum Potential Contributions to Future Sea Level Rise from Polar Ice Sheets

NASA Astrophysics Data System (ADS)

Deconto, R. M.; Pollard, D.

2017-12-01

New climate and ice-sheet modeling, calibrated to past changes in sea-level, is painting a stark picture of the future fate of the great polar ice sheets if greenhouse gas emissions continue unabated. This is especially true for Antarctica, where a substantial fraction of the ice sheet rests on bedrock more than 500-meters below sea level. Here, we explore the sensitivity of the polar ice sheets to a warming atmosphere and ocean under a range of future greenhouse gas emissions scenarios. The ice sheet-climate-ocean model used here considers time-evolving changes in surface mass balance and sub-ice oceanic melting, ice deformation, grounding line retreat on reverse-sloped bedrock (Marine Ice Sheet Instability), and newly added processes including hydrofracturing of ice shelves in response to surface meltwater and rain, and structural collapse of thick, marine-terminating ice margins with tall ice-cliff faces (Marine Ice Cliff Instability). The simulations improve on previous work by using 1) improved atmospheric forcing from a Regional Climate Model and 2) a much wider range of model physical parameters within the bounds of modern observations of ice dynamical processes (particularly calving rates) and paleo constraints on past ice-sheet response to warming. Approaches to more precisely define the climatic thresholds capable of triggering rapid and potentially irreversible ice-sheet retreat are also discussed, as is the potential for aggressive mitigation strategies like those discussed at the 2015 Paris Climate Conference (COP21) to substantially reduce the risk of extreme sea-level rise. These results, including physics that consider both ice deformation (creep) and calving (mechanical failure of marine terminating ice) expand on previously estimated limits of maximum rates of future sea level rise based solely on kinematic constraints of glacier flow. At the high end, the new results show the potential for more than 2m of global mean sea level rise by 2100, implying that physically plausible upper limits on future sea-level rise might need to be reconsidered.

Altitude transitions in energy climbs

NASA Technical Reports Server (NTRS)

Weston, A. R.; Cliff, E. M.; Kelley, H. J.

1982-01-01

The aircraft energy-climb trajectory for configurations with a sharp transonic drag rise is well known to possess two branches in the altitude/Mach-number plane. Transition in altitude between the two branches occurs instantaneously, a 'corner' in the minimum-time solution obtained with the energy-state model. If the initial and final values of altitude do not lie on the energy-climb trajectory, then additional jumps (crude approximations to dives and zooms) are required at the initial and terminal points. With a singular-perturbation approach, a 'boundary-layer' correction is obtained for each altitude jump, the transonic jump being a so-called 'internal' boundary layer, different in character from the initial and terminal layers. The determination of this internal boundary layer is examined and some computational results for an example presented.

Current-day matters of administration and law in the field of high-rise construction

NASA Astrophysics Data System (ADS)

Voskresenskaya, Elena; Snetkov, Vitaly; Tebryaev, Alexander

2018-03-01

The article touches upon main reasons for high-rise construction: increase in energy consumption and limited availability of site in the big cities of Russia. Increase in energy consumption is related with construction, transportation and applying of ventilation and air conditioning systems. Nowadays, there are developed a lot of design and engineer solutions, that include autonomous systems as well as passive methods with low energy consumption rate, which are interrelated with local climate conditions. Certain architectural solutions contribute to energy consumption decrease: building orientation with respect to the cardinal directions, taking into account the prevailing cold wind directions, maximum glazing of the southern facades and minimum glazing of the northern ones, what plays a big role in hard climate conditions. Limited availability of site for construction in the big cities resulted in rapid development of the high-rise construction, which today prevails in terms of quantitative indicators of civil engineering.

A note on some statistical properties of rise time parameters used in muon arrival time measurements

NASA Technical Reports Server (NTRS)

Vanderwalt, D. J.; Devilliers, E. J.

1985-01-01

Most investigations of the muon arrival time distribution in EAS during the past decade made use of parameters which can collectively be called rise time parameters. The rise time parameter T sub A/B is defined as the time taken for the integrated pulse from a detector to rise from A% to B% of its full amplitude. The use of these parameters are usually restricted to the determination of the radial dependence thereof. This radial dependence of the rise time parameters are usually taken as a signature of the particle interaction characteristics in the shower. As these parameters have a stochastic nature, it seems reasonable that one should also take notice of this aspect of the rise time parameters. A statistical approach to rise time parameters is presented.

Estimating the Size and Timing of Maximum Amplitude for Cycle 23 from Its Early Cycle Behavior

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1998-01-01

On the basis of the lowest observed smoothed monthly mean sunspot number, cycle 23 appears to have conventionally begun in May 1996, in conjunction with the first appearance of a new cycle, high-latitude spot-group. Such behavior, however, is considered rather unusual, since, previously (based upon the data- available cycles 12-22), the first appearance of a new cycle, high-latitude spot- group has always preceded conventional onset by at least 3 months. Furthermore, accepting May 1996 as the official start for cycle 23 poses a dilemma regarding its projected size and timing of maximum amplitude. Specifically, from the max-min and amplitude-period relationships we infer that cycle 23 should be above average in size and a fast riser, with maximum amplitude occurring before May 2000 (being in agreement with projections for cycle 23 based on precursor information), yet from its initial languid rate of rise (during the first 6 months of the cycle) we infer that it should be below average in size and a slow riser, with maximum amplitude occurring after May 2000. The dilemma vanishes, however, when we use a slightly later-occurring onset. For example, using August 1996, a date associated with a local secondary minimum prior to the rapid rise that began shortly thereafter (in early 1997), we infer that cycle 23's rate of rise is above that for the mean of cycles 1-22, the mean of cycles 10-22 (the modern era cycles), the mean of the modern era'fast risers,' and the largest of the modern era 'slow risers' (i.e., cycle 20), thereby, suggesting that cycle 23 will be both fast-rising and above average in size, peaking before August 2000. Additionally, presuming cycle 23 to be a well- behaved fast-rising cycle (regardless of whichever onset date is used), we also infer that its maximum amplitude likely will measure about 144.0 q+/- 28.8 (from the general behavior found for the bulk of modern era fast risers; i.e., 5 of 7 have had their maximum amplitude to lie within 20% of the mean curve for modern era fast risers). It is apparent, then, that sunspot number growth during 1998 will prove crucial for correctly establishing the size and shape of cycle 23.

Minimum time and fuel flight profiles for an F-15 airplane with a Highly Integrated Digital Electronic Control (HIDEC) system

NASA Technical Reports Server (NTRS)

Haering, E. A., Jr.; Burcham, F. W., Jr.

1984-01-01

A simulation study was conducted to optimize minimum time and fuel consumption paths for an F-15 airplane powered by two F100 Engine Model Derivative (EMD) engines. The benefits of using variable stall margin (uptrim) to increase performance were also determined. This study supports the NASA Highly Integrated Digital Electronic Control (HIDEC) program. The basis for this comparison was minimum time and fuel used to reach Mach 2 at 13,716 m (45,000 ft) from the initial conditions of Mach 0.15 at 1524 m (5000 ft). Results were also compared to a pilot's estimated minimum time and fuel trajectory determined from the F-15 flight manual and previous experience. The minimum time trajectory took 15 percent less time than the pilot's estimate for the standard EMD engines, while the minimum fuel trajectory used 1 percent less fuel than the pilot's estimate for the minimum fuel trajectory. The F-15 airplane with EMD engines and uptrim, was 23 percent faster than the pilot's estimate. The minimum fuel used was 5 percent less than the estimate.

Model predictive control of attitude maneuver of a geostationary flexible satellite based on genetic algorithm

NASA Astrophysics Data System (ADS)

TayyebTaher, M.; Esmaeilzadeh, S. Majid

2017-07-01

This article presents an application of Model Predictive Controller (MPC) to the attitude control of a geostationary flexible satellite. SIMO model has been used for the geostationary satellite, using the Lagrange equations. Flexibility is also included in the modelling equations. The state space equations are expressed in order to simplify the controller. Naturally there is no specific tuning rule to find the best parameters of an MPC controller which fits the desired controller. Being an intelligence method for optimizing problem, Genetic Algorithm has been used for optimizing the performance of MPC controller by tuning the controller parameter due to minimum rise time, settling time, overshoot of the target point of the flexible structure and its mode shape amplitudes to make large attitude maneuvers possible. The model included geosynchronous orbit environment and geostationary satellite parameters. The simulation results of the flexible satellite with attitude maneuver shows the efficiency of proposed optimization method in comparison with LQR optimal controller.

State-Of High Brightness RF Photo-Injector Design

NASA Astrophysics Data System (ADS)

Ferrario, Massimo; Clendenin, Jym; Palmer, Dennis; Rosenzweig, James; Serafini, Luca

2000-04-01

The art of designing optimized high brightness electron RF Photo-Injectors has moved in the last decade from a cut and try procedure, guided by experimental experience and time consuming particle tracking simulations, up to a fast parameter space scanning, guided by recent analytical results and a fast running semi-analytical code, so to reach the optimum operating point which corresponds to maximum beam brightness. Scaling laws and the theory of invariant envelope provide to the designers excellent tools for a first parameters choice and the code HOMDYN, based on a multi-slice envelope description of the beam dynamics, is tailored to describe the space charge dominated dynamics of laminar beams in presence of time dependent space charge forces, giving rise to a very fast modeling capability for photo-injectors design. We report in this talk the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector. During this work a new effective working point for a split RF photoinjector has been discovered by means of the previous mentioned approach. By a proper choice of rf gun and solenoid parameters, the emittance evolution shows a double minimum behavior in the drifting region. If the booster is located where the relative emittance maximum and the envelope waist occur, the second emittance minimum can be shifted at the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat top bunch), to the extent that the invariant envelope matching conditions are satisfied.

Impacts of PM concentrations on visibility impairment

NASA Astrophysics Data System (ADS)

Jie, Guo; Wang, Mei-mei; Han, Ye-Xing; Yu, Zhi-Wei; Tang, Huai-Wu

2016-11-01

In the paper, an accurate and sensitive cavity attenuated phase shift spectroscopy (CAPS) sensor was used to monitor the atmospheric visibility. The CAPS system mainly includes a LED light source, a band-pass filter, an optical resonant cavity (composed of two high mirror, reflectivity is greater than 99.99%), a photoelectric detector and a lock-in amplifier. The 2L/min flow rate, the optical sensor rise and fall response time is about 15 s, so as to realize the fast measurement of visibility. An Allan variance analysis was carried out evaluating the optical system stability (and hence the maximum averaging time for the minimum detection limit) of the CAPS system. The minima ( 0.1 Mm-1) in the Allan plots show the optimum average time ( 100s) for optimum detection performance of the CAPS system. During this period, the extinction coefficient was correlated with PM2.5 mass (0.88), the extinction coefficient was correlated with PM10 mass (0.85). The atmospheric visibility was correlated with PM2.5 mass (0.74). The atmospheric visibility was correlated with PM10 mass (0.66).

Relaxation and turbulence effects on sonic boom signatures

NASA Technical Reports Server (NTRS)

Pierce, Allan D.; Sparrow, Victor W.

1992-01-01

The rudimentary theory of sonic booms predicts that the pressure signatures received at the ground begin with an abrupt shock, such that the overpressure is nearly abrupt. This discontinuity actually has some structure, and a finite time is required for the waveform to reach its peak value. This portion of the waveform is here termed the rise phase, and it is with this portion that this presentation is primarily concerned. Any time characterizing the duration of the rise phase is loosely called the 'rise time.' Various definitions are used in the literature for this rise time. In the present discussion the rise time can be taken as the time for the waveform to rise from 10 percent of its peak value to 90 percent of its peak value. The available data on sonic booms that appears in the open literature suggests that typical values of shock over-pressure lie in the range of 30 Pa to 200 Pa, typical values of shock duration lie in the range of 150 ms to 250 ms, and typical values of the rise time lie in the range of 1 ms to 5 ms. The understanding of the rise phase of sonic booms is important because the perceived loudness of a shock depends primarily on the structure of the rise phase. A longer rise time typically implies a less loud shock. A primary question is just what physical mechanisms are most important for the determination of the detailed structure of the rise phase.

Rise in the frequency of cloud cover in LANDSAT data for the period 1973 to 1981. [Brazil

NASA Technical Reports Server (NTRS)

Parada, N. D. J. (Principal Investigator); Mendonca, F. J.; Neto, G. C.

1983-01-01

Percentages of cloud cover in LANDSAT imagery were used to calculate the cloud cover monthly average statistic for each LANDSAT scene in Brazil, during the period of 1973 to 1981. The average monthly cloud cover and the monthly minimum cloud cover were also calculated for the regions of north, northeast, central west, southeast and south, separately.

Modified Augmented Renal Clearance Score Predicts Rapid Piperacillin and Tazobactam Clearance in Critically Ill Surgery and Trauma Patients

DTIC Science & Technology

2014-04-24

intermittent dosing regimens. CONCLUSION: Given its ability to predict antimicrobial clearance above populationmedians, which could compromise therapy, the...campaign dedicated to improve out- comes.1,2 In the era ofmultiply drug- resistant pathogens and rising antimicrobial minimum inhibitory concentrations (MICs...urinary creatinine clearance significantly exceeds what is predicted by the serum creatinine concentration according to various mathematical

Measurement of Capillary Radius and Contact Angle within Porous Media.

PubMed

Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

2015-12-01

The pore radius (i.e., capillary radius) and contact angle determine the capillary pressure generated in a porous medium. The most common method to determine these two parameters is through measurement of the capillary pressure generated by a reference liquid (i.e., a liquid with near-zero contact angle) and a test liquid. The rate of rise technique, commonly used to determine the capillary pressure, results in significant uncertainties. In this study, we utilize a recently developed technique for independently measuring the capillary pressure and permeability to determine the equivalent minimum capillary radii and contact angle of water within micropillar wick structures. In this method, the experimentally measured dryout threshold of a wick structure at different wicking lengths is fit to Darcy's law to extract the maximum capillary pressure generated by the test liquid. The equivalent minimum capillary radii of different wick geometries are determined by measuring the maximum capillary pressures generated using n-hexane as the working fluid. It is found that the equivalent minimum capillary radius is dependent on the diameter of pillars and the spacing between pillars. The equivalent capillary radii of micropillar wicks determined using the new method are found to be up to 7 times greater than the current geometry-based first-order estimates. The contact angle subtended by water at the walls of the micropillars is determined by measuring the capillary pressure generated by water within the arrays and the measured capillary radii for the different geometries. This mean contact angle of water is determined to be 54.7°.

Nucleation theory with delayed interactions: An application to the early stages of the receptor-mediated adhesion/fusion kinetics of lipid vesicles

NASA Astrophysics Data System (ADS)

Raudino, Antonio; Pannuzzo, Martina

2010-01-01

A semiquantitative theory aimed to describe the adhesion kinetics between soft objects, such as living cells or vesicles, has been developed. When rigid bodies are considered, the adhesion kinetics is successfully described by the classical Derjaguin, Landau, Verwey, and Overbeek (DLVO) picture, where the energy profile of two approaching bodies is given by a two asymmetrical potential wells separated by a barrier. The transition probability from the long-distance to the short-distance minimum defines the adhesion rate. Conversely, soft bodies might follow a different pathway to reach the short-distance minimum: thermally excited fluctuations give rise to local protrusions connecting the approaching bodies. These transient adhesion sites are stabilized by short-range adhesion forces (e.g., ligand-receptor interactions between membranes brought at contact distance), while they are destabilized both by repulsive forces and by the elastic deformation energy. Above a critical area of the contact site, the adhesion forces prevail: the contact site grows in size until the complete adhesion of the two bodies inside a short-distance minimum is attained. This nucleation mechanism has been developed in the framework of a nonequilibrium Fokker-Planck picture by considering both the adhesive patch growth and dissolution processes. In addition, we also investigated the effect of the ligand-receptor pairing kinetics at the adhesion site in the time course of the patch expansion. The ratio between the ligand-receptor pairing kinetics and the expansion rate of the adhesion site is of paramount relevance in determining the overall nucleation rate. The theory enables one to self-consistently include both thermodynamics (energy barrier height) and dynamic (viscosity) parameters, giving rise in some limiting cases to simple analytical formulas. The model could be employed to rationalize fusion kinetics between vesicles, provided the short-range adhesion transition is the rate-limiting step to the whole adhesion process. Approximate relationships between the experimental fusion rates reported in the literature and parameters such as membrane elastic bending modulus, repulsion strength, temperature, osmotic forces, ligand-receptor binding energy, solvent and membrane viscosities are satisfactory explained by our model. The present results hint a possible role of the initial long-distance→short-distance transition in determining the whole fusion kinetics.

Nucleation theory with delayed interactions: an application to the early stages of the receptor-mediated adhesion/fusion kinetics of lipid vesicles.

PubMed

Raudino, Antonio; Pannuzzo, Martina

2010-01-28

A semiquantitative theory aimed to describe the adhesion kinetics between soft objects, such as living cells or vesicles, has been developed. When rigid bodies are considered, the adhesion kinetics is successfully described by the classical Derjaguin, Landau, Verwey, and Overbeek (DLVO) picture, where the energy profile of two approaching bodies is given by a two asymmetrical potential wells separated by a barrier. The transition probability from the long-distance to the short-distance minimum defines the adhesion rate. Conversely, soft bodies might follow a different pathway to reach the short-distance minimum: thermally excited fluctuations give rise to local protrusions connecting the approaching bodies. These transient adhesion sites are stabilized by short-range adhesion forces (e.g., ligand-receptor interactions between membranes brought at contact distance), while they are destabilized both by repulsive forces and by the elastic deformation energy. Above a critical area of the contact site, the adhesion forces prevail: the contact site grows in size until the complete adhesion of the two bodies inside a short-distance minimum is attained. This nucleation mechanism has been developed in the framework of a nonequilibrium Fokker-Planck picture by considering both the adhesive patch growth and dissolution processes. In addition, we also investigated the effect of the ligand-receptor pairing kinetics at the adhesion site in the time course of the patch expansion. The ratio between the ligand-receptor pairing kinetics and the expansion rate of the adhesion site is of paramount relevance in determining the overall nucleation rate. The theory enables one to self-consistently include both thermodynamics (energy barrier height) and dynamic (viscosity) parameters, giving rise in some limiting cases to simple analytical formulas. The model could be employed to rationalize fusion kinetics between vesicles, provided the short-range adhesion transition is the rate-limiting step to the whole adhesion process. Approximate relationships between the experimental fusion rates reported in the literature and parameters such as membrane elastic bending modulus, repulsion strength, temperature, osmotic forces, ligand-receptor binding energy, solvent and membrane viscosities are satisfactory explained by our model. The present results hint a possible role of the initial long-distance-->short-distance transition in determining the whole fusion kinetics.

Assessing the impact of edaphic factors on coastal ecosystem functions in a tropical island using electromagnetic-induction

NASA Astrophysics Data System (ADS)

Lynch, N. E.; Wuddivira, M.; Oatham, M.

2013-12-01

The small islands in the low-lying states of the Caribbean Basin are among the most vulnerable to sea level rise caused by climate change. Bequia, a tropical Grenadine island, is particularly susceptible due to its small land mass, limited natural resources and an economy that is touristic and marine based. Consultation with stakeholders on sustainable livelihoods revealed that degradation of the coastal ecosystem is occurring with progressing time. Consequently, the island is losing its beneficial ecosystem services and its natural attractiveness leading to declining revenue base, increasing food security risk and job losses. We propose that with sea level rise, soil salinity increases further inland leading to degradation of coastal zones and ecosystem functions. Using geophysical techniques and standard sampling procedures we observationally investigated the spatial and temporal impacts of soil salinization due to sea level changes on the ecosystem functions of five coastal areas in the seven square mile island of Bequia. We analyzed soil, tidal, rainfall data and historical aerial imagery to assess the impact of soil salinity on the ecosystem of Bequia. Our results show extreme seasonal salinity variability with increased salinity inland during the dry season months of January to May. This was significantly influenced by the fluctuation of seasonal water content and temperature. A complete time-based analysis ensures the development of adaptation strategies to coastal change for sustainable provisioning of ecosystem services for Bequia and other Caribbean Islands with minimum ecological and economic losses.

The one hundredth year of Rudolf Wolf's death: Do we have the correct reconstruction of solar activity?

NASA Technical Reports Server (NTRS)

Hoyt, Douglas V.; Schatten, Kenneth H.; Nesmes-Ribes, Elizabeth

1994-01-01

In the one hundred years since Wolf died, little effort has gone into research to see if improved reconstructions of sunspot numbers can be made. We have gathered more than 349,000 observations of daily sunspot group counts from more than 350 observers active from 1610 to 1993. Based upon group counts alone, it is possible to make an objective and homogeneous reconstruction of sunspot numbers. From our study, it appears that the Sun has steadily increased in activity since 1700 with the exception of a brief decrease in the Dalton Minimum (1795-1823). The significant results here are the greater depth of the Dalton Minimum, the generally lower activity throughout the 1700's, and the gradual rise in activity from the Maunder Minimum to the present day. This solar activity reconstruction is quite similar to those Wolf published before 1868 rather than the revised Wolf reconstructions after 1873 which used geomagnetic fluctuations.

Detecting anthropogenic footprints in regional and global sea level rise since 1900

NASA Astrophysics Data System (ADS)

Dangendorf, S.; Marcos, M.; Piecuch, C. G.; Jensen, J.

2015-12-01

While there is scientific consensus that global and local mean sea level (GMSL and LMSL) is rising since the late 19th century, it remains unclear how much of this rise is due to natural variability or anthropogenic forcing. Distinguishing both contributions requires an extensive knowledge about the persistence of natural high and low stands in GMSL and LMSL. This is challenging, since observational time series represent the superposition of various processes with different spectral properties. Here we provide a probabilistic upper range of long-term persistent natural GMSL/LMSL variability (P=0.99), which in turn determines the minimum/maximum anthropogenic contribution since 1900. To account for different spectral characteristics of various contributing processes, we separate LMSL (corrected for vertical land motion) into a slowly varying volumetric (mass and density changes) and a more rapidly changing atmospheric component. Based on a combination of spectral analyses of tide gauge records, barotropic and baroclinic ocean models and numerical Monte-Carlo experiments, we find that in records where transient atmospheric processes dominate the spectra, the persistence of natural volumetric changes tends to be underestimated. If each component is assessed separately, natural centennial trends are locally up to ~1.0 mm/yr larger than in case of an integrated assessment, therefore erroneously enhancing the significance of anthropogenic footprints. The GMSL, however, remains unaffected by such biases. On the basis of a model assessment of the separate components, we conclude that it is virtually certain (P=0.99) that at least 45% of the observed increase in GMSL is of anthropogenic origin.

Warming and wetting signals emerging from analysis of changes in climate extreme indices over South America

NASA Astrophysics Data System (ADS)

Skansi, María de los Milagros; Brunet, Manola; Sigró, Javier; Aguilar, Enric; Arevalo Groening, Juan Andrés; Bentancur, Oscar J.; Castellón Geier, Yaruska Rosa; Correa Amaya, Ruth Leonor; Jácome, Homero; Malheiros Ramos, Andrea; Oria Rojas, Clara; Pasten, Alejandro Max; Sallons Mitro, Sukarni; Villaroel Jiménez, Claudia; Martínez, Rodney; Alexander, Lisa V.; Jones, P. D.

2013-01-01

Here we show and discuss the results of an assessment of changes in both area-averaged and station-based climate extreme indices over South America (SA) for the 1950-2010 and 1969-2009 periods using high-quality daily maximum and minimum temperature and precipitation series. A weeklong regional workshop in Guayaquil (Ecuador) provided the opportunity to extend the current picture of changes in climate extreme indices over SA. Our results provide evidence of warming and wetting across the whole SA since the mid-20th century onwards. Nighttime (minimum) temperature indices show the largest rates of warming (e.g. for tropical nights, cold and warm nights), while daytime (maximum) temperature indices also point to warming (e.g. for cold days, summer days, the annual lowest daytime temperature), but at lower rates than for minimums. Both tails of night-time temperatures have warmed by a similar magnitude, with cold days (the annual lowest nighttime and daytime temperatures) seeing reductions (increases). Trends are strong and moderate (moderate to weak) for regional-averaged (local) indices, most of them pointing to a less cold SA during the day and warmer night-time temperatures. Regionally-averaged precipitation indices show clear wetting and a signature of intensified heavy rain events over the eastern part of the continent. The annual amounts of rainfall are rising strongly over south-east SA (26.41 mm/decade) and Amazonia (16.09 mm/decade), but north-east Brazil and the western part of SA have experienced non-significant decreases. Very wet and extremely days, the annual maximum 5-day and 1-day precipitation show the largest upward trends, indicating an intensified rainfall signal for SA, particularly over Amazonia and south-east SA. Local trends for precipitation extreme indices are in general less coherent spatially, but with more general spatially coherent upward trends in extremely wet days over all SA.

Selecting the best tone-pip stimulus-envelope time for estimating an objective middle-latency response threshold for low- and middle-tone sensorineural hearing losses.

PubMed

Xu, Z M; De Vel, E; Vinck, B; Van Cauwenberge, P

1995-01-01

The effects of rise-fall and plateau times for the Pa component of the middle-latency response (MLR) were investigated in normally hearing subjects, and an objective MLR threshold was measured in patients with low- and middle-tone hearing losses, using a selected stimulus-envelope time. Our results showed that the stimulus-envelope time (the rise-fall time and plateau time groups) affected the Pa component of the MLR (quality was determined by the (chi 2-test and amplitude by the F-test). The 4-2-4 tone-pips produced good Pa quality by visual inspection. However, our data revealed no statistically significant Na-Pa amplitude differences between the two subgroups studied when comparing the 2- and 4-ms rise-fall times and the 0- and 2-ms plateau times. In contrast, Na-Pa became significantly smaller from the 4-ms to the 6-ms rise-fall time and from the 2-ms to the 4-ms plateau time (paired t-test). This result allowed us to select the 2- or 4-ms rise-fall time and the 0- or 2-ms plateau time without influencing amplitude. Analysis of the stimulus spectral characteristics demonstrated that a rise-fall time of at least 2ms could prevent spectral splatter and indicated that a stimulus with a 5-ms rise-fall time had a greater frequency-specificity than a stimulus of 2-ms rise-fall time. When considering the synchronous discharge and frequency-specificity of MLR, our findings show that a rise-fall time of four periods with a plateau of two periods is an acceptable compromise for estimating the objective MLR threshold.(ABSTRACT TRUNCATED AT 250 WORDS)

Signals from the planets, via the Sun to the Earth

NASA Astrophysics Data System (ADS)

Solheim, J.-E.

2013-12-01

The best method for identification of planetary forcing of the Earth's climate is to investigate periodic variations in climate time series. Some natural frequencies in the Earth climate system seem to be synchronized to planetary cycles, and amplified to a level of detection. The response by the Earth depends on location, and in global averaged series, some planetary signals may be below detection. Comparing sea level rise with sunspot variations, we find phase variations, and even a phase reversal. A periodogram of the global temperature shows that the Earth amplifies other periods than observed in sunspots. A particular case is that the Earth amplifies the 22 yr Hale period, and not the 11 yr Schwabe period. This may be explained by alternating peak or plateau appearance of cosmic ray counts. Among longer periods, the Earth amplifies the 60 yr planetary period and keeps the phase during centennials. The recent global warming may be interpreted as a rising branch of a millennium cycle, identified in ice cores and sediments and also recorded in history. This cycle peaks in the second half of this century, and then a 500 yr cooling trend will start. An expected solar grand minimum due to a 200 yr cycle will introduce additional cooling in the first part of this century.

What the Sunspot Record Tells Us About Space Climate

NASA Technical Reports Server (NTRS)

Hathaway, David H.; Wilson, Robert M.

2004-01-01

The records concerning the number, sizes, and positions of sunspots provide a direct means of characterizing solar activity over nearly 400 years. Sunspot numbers are strongly correlated with modem measures of solar activity including: 10.7-cm radio flux, total irradiance, x-ray flares, sunspot area, the baseline level of geomagnetic activity, and the flux of galactic cosmic rays. The Group Sunspot Number provides information on 27 sunspot cycles, far more than any of the modem measures of solar activity, and enough to provide important details about long-term variations in solar activity or Space Climate. The sunspot record shows: 1) sunspot cycles have periods of 131 plus or minus 14 months with a normal distribution; 2) sunspot cycles are asymmetric with a fast rise and slow decline; 3) the rise time from minimum to maximum decreases with cycle amplitude; 4) large amplitude cycles are preceded by short period cycles; 5 ) large amplitude cycles are preceded by high minima; 6) although the two hemispheres remain linked in phase, there are significant asymmetries in the activity in each hemisphere; 7) the rate at which the active latitudes drift toward the equator is anti-correlated with the cycle period, 8) the rate at which the active latitudes drift toward the equator is positively correlated with the amplitude of the cycle after the next; 9) there has been a significant secular increase in the amplitudes of the sunspot cycles since the end of the Maunder Minimum (1715); and 10) there is weak evidence for a quasi-periodic variation in the sunspot cycle amplitudes with a period of about 90 years. These characteristics indicate that the next solar cycle should have a maximum smoothed sunspot number of about 1.45 plus or minus 30 in 2010 while the following cycle should have a maximum of about 70 plus or minus 30 in 2023.

Proton exchange membrane fuel cells cold startup global strategy for fuel cell plug-in hybrid electric vehicle

NASA Astrophysics Data System (ADS)

Henao, Nilson; Kelouwani, Sousso; Agbossou, Kodjo; Dubé, Yves

2012-12-01

This paper investigates the Proton Exchange Membrane Fuel Cell (PEMFC) Cold Startup problem within the specific context of the Plugin Hybrid Electric Vehicles (PHEV). A global strategy which aims at providing an efficient method to minimize the energy consumption during the startup of a PEMFC is proposed. The overall control system is based on a supervisory architecture in which the Energy Management System (EMS) plays the role of the power flow supervisor. The EMS estimates in advance, the time to start the fuel cell (FC) based upon the battery energy usage during the trip. Given this estimation and the amount of additional energy required, the fuel cell temperature management strategy computes the most appropriate time to start heating the stack in order to reduce heat loss through the natural convection. As the cell temperature rises, the PEMFC is started and the reaction heat is used as a self-heating power source to further increase the stack temperature. A time optimal self-heating approach based on the Pontryagin minimum principle is proposed and tested. The experimental results have shown that the proposed approach is efficient and can be implemented in real-time on FC-PHEVs.

Upstream proton cyclotron waves at Venus near solar maximum

NASA Astrophysics Data System (ADS)

Delva, M.; Bertucci, C.; Volwerk, M.; Lundin, R.; Mazelle, C.; Romanelli, N.

2015-01-01

magnetometer data of Venus Express are analyzed for the occurrence of waves at the proton cyclotron frequency in the spacecraft frame in the upstream region of Venus, for conditions of rising solar activity. The data of two Venus years up to the time of highest sunspot number so far (1 Mar 2011 to 31 May 2012) are studied to reveal the properties of the waves and the interplanetary magnetic field (IMF) conditions under which they are observed. In general, waves generated by newborn protons from exospheric hydrogen are observed under quasi- (anti)parallel conditions of the IMF and the solar wind velocity, as is expected from theoretical models. The present study near solar maximum finds significantly more waves than a previous study for solar minimum, with an asymmetry in the wave occurrence, i.e., mainly under antiparallel conditions. The plasma data from the Analyzer of Space Plasmas and Energetic Atoms instrument aboard Venus Express enable analysis of the background solar wind conditions. The prevalence of waves for IMF in direction toward the Sun is related to the stronger southward tilt of the heliospheric current sheet for the rising phase of Solar Cycle 24, i.e., the "bashful ballerina" is responsible for asymmetric background solar wind conditions. The increase of the number of wave occurrences may be explained by a significant increase in the relative density of planetary protons with respect to the solar wind background. An exceptionally low solar wind proton density is observed during the rising phase of Solar Cycle 24. At the same time, higher EUV increases the ionization in the Venus exosphere, resulting in higher supply of energy from a higher number of newborn protons to the wave. We conclude that in addition to quasi- (anti)parallel conditions of the IMF and the solar wind velocity direction, the higher relative density of Venus exospheric protons with respect to the background solar wind proton density is the key parameter for the higher number of observable proton cyclotron waves near solar maximum.

Coronal and heliospheric magnetic flux circulation and its relation to open solar flux evolution

NASA Astrophysics Data System (ADS)

Lockwood, Mike; Owens, Mathew J.; Imber, Suzanne M.; James, Matthew K.; Bunce, Emma J.; Yeoman, Timothy K.

2017-06-01

Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle. All flux emergence causes a rise then a fall in OSF, but only OSF with foot points in opposing hemispheres progresses the solar cycle via the evolution of the polar fields. Emergence in one hemisphere, or symmetric emergence without some form of foot point exchange across the heliographic equator, causes poleward migrating fields of both polarities in one or both (respectively) hemispheres which temporarily enhance OSF but do not advance the polar field cycle. The heliospheric field observed near Mercury and Earth reflects the asymmetries in emergence. Using magnetograms, we find evidence that the poleward magnetic flux transport (of both polarities) is modulated by the HCS tilt, revealing an effect on OSF loss rate. The declining phase rise in OSF was caused by strong emergence in the southern hemisphere with an anomalously low HCS tilt. This implies the recent fall in the southern polar field will be sustained and that the peak OSF has limited implications for the polar field at the next sunspot minimum and hence for the amplitude of cycle 25.