OUT-OF-STEP DETECTION BASED ON ZUBOV’S APPROXIMATION BOUNDARY METHOD

Disturbances in power systems may lead to electromagnetic transient oscillations due to mismatch of mechanical input power and electrical output power. Out-of-step conditions in power system are common after the disturbances where the continuous oscillations do not damp out and the system becomes unstable. Existing out-of-step detection methods are system specific as extensive off-line studies are required for setting of relays. Most of the existing algorithms also require network reduction techniques to apply in multi-machine power systems. To overcome these issues, this research applies Phasor Measurement Unit (PMU) data and Zubov’s approximation stability boundary method, which is a modification of Lyapunov’s direct method, to develop a novel out-of-step detection algorithm. The proposed out-of-step detection algorithm is tested in a Single Machine Infinite Bus system, IEEE 3-machine 9-bus, and IEEE 10-machine 39-bus systems. Simulation results show that the proposed algorithm is capable of detecting out-of-step conditions in multi-machine power systems without using network reduction techniques and a comparative study with an existing blinder method demonstrate that the decision times are faster. The simulation case studies also demonstrate that the proposed algorithm does not depend on power system parameters, hence it avoids the need of extensive off-line system studies as needed in other algorithms.

The Getting-Out-of-Bed (GoB) scale: a measure of motivation and life outlook in older adults with cancer

OBJECTIVE: To develop and evaluate the psychometric properties of a measure of motivation and life outlook (Getting-Out-of-Bed [GoB]). DESIGN: Secondary analysis of baseline and 6-month data from a longitudinal follow-up study of older breast cancer survivors. PARTICIPANTS: Women (N = 660) diagnosed with primary breast cancer stage I-IIIA disease, age >or=65 years, and permission to contact from an attending physician in four geographic regions in the United States (city-based Los Angeles, California; statewide in Minnesota, North Carolina, and Rhode Island). MEASUREMENT: Data were collected over 6-months of follow-up from consenting patients' medical records and telephone interviews with patients. Data collected included the 4-item GoB, health-related quality of life (HRQoL), breast cancer, sociodemographic, and health-related characteristics. RESULTS: Factor analysis produced, as hypothesized, one principal component with eigen values of 2.74(baseline) and 2.91(6-months) which explained 68.6%(baseline) and 72.7%(6-months) of total variance. In further psychometric analyses, GoB exhibited good construct validity (divergent: low nonstatistically significant correlations with unrelated constructs; convergent: moderate statistically significant correlations with related constructs; discriminant: distinguished high HRQoL groups with a high level of significance), excellent internal reliability (Cronbach's alpha 0.84(baseline), 0.87(6-months)), and produced stable measurements over 6-months. Women with GoB scores >or=50 at baseline were more likely at 6-months to have good HRQoL, good self-perceived health, and report regular exercise, indicating good predictive ability. CONCLUSION: GoB demonstrated overall good psychometric properties in this sample of older breast cancer survivors, suggestive of a promising tool for assessing motivation and life outlook in older adults. Nevertheless, because it was developed and initially evaluated in a select sample, using measures with similar but not exact content overlap further evaluation is needed before it can be recommended for widespread use.

The Influence of MGA and PG600 on the Out of Season Reproductive Performance of Ewes

Seasonal lamb supply has been established as one of the major hindrances to the American sheep industry. The ability to consistently lamb ewes on an accelerated production system offers additional benefits of reduced maintenance costs, more uniform cash flow along with reduced labor and facility demands. Previous work at McNay with spring breeding indicated that light priming rams regardless of genetic base improved conception rates, however, MGA feeding postweaning gave inconsistent and sometimes depressed reproductive activity in ewes. This study was conducted to evaluate the use of MGA in late lactation and a single PG600 injection at weaning, either individually or in combination.

Dual dispatch early defibrillation in out-of-hospital cardiac arrest in a mixed urban–rural population

Aims The effects of a system based on minimally trained first responders (FR) dispatched simultaneously with the emergency medical services (EMS) of the local hospital in a mixed urban and rural area in Northwestern Switzerland were examined. Methods and results In this prospective study 500 voluntary fire fighters received a 4-h training in basic-life-support using automated-external-defibrillation (AED). FR and EMS were simultaneously dispatched in a two-tier rescue system. During the years 2001–2008, response times, resuscitation interventions and outcomes were monitored. 1334 emergencies were included. The FR reached the patients (mean age 60.4 ± 19 years; 65% male) within 6 ± 3 min after emergency calls compared to 12 ± 5 min by the EMS (p < 0.0001). Seventy-six percent of the 297 OHCAs occurred at home. Only 3 emergencies with resuscitation attempts occurred at the main railway station equipped with an on-site AED. FR were on the scene before arrival of the EMS in 1166 (87.4%) cases. Of these, the FR used AED in 611 patients for monitoring or defibrillation. CPR was initiated by the FR in 164 (68.9% of 238 resuscitated patients). 124 patients were defibrillated, of whom 93 (75.0%) were defibrillated first by the FR. Eighteen patients (of whom 13 were defibrillated by the FR) were discharged from hospital in good neurological condition. Conclusions Minimally trained fire fighters integrated in an EMS as FR contributed substantially to an increase of the survival rate of OHCAs in a mixed urban and rural area.

The “Out of Africa Tribe” (II): Paleolithic warriors with big canoes and protective weapons

It is generally difficult to establish a timeline for the appearance of different technologies and tools during human cultural evolution. Here I use stochastic character mapping of discrete traits using human mtDNA phylogenies rooted to the Reconstructed Sapiens Reference Sequence (RSRS) as a model to address this question. The analysis reveals that the ancestral state of Homo sapiens was hunting, using material innovations that included bows and arrows, stone axes and spears. However, around 80,000 y before present, a transition occurred, from this ancestral hunting tradition, toward the invention of protective weapons such as shields, the appearance of ritual fighting as a socially accepted behavior and the construction of war canoes for the fast transport of large numbers of warriors. This model suggests a major cultural change, during the Palaeolithic, from hunters to warriors. Moreover, in the light of the recent Out of Africa Theory, it suggests that the “Out of Africa Tribe” was a tribe of warriors that had developed protective weapons such as shields and used big war canoes to travel the sea coast and big rivers in raiding expeditions.

Subcritical Propagation and Coalescence of Oil-Filled Cracks: Getting the Oil Out of Low-Permeability Source Rocks

We use a fracture mechanics model to study subcritical propagation and coalescence of single and collinear oil-filled cracks during conversion of kerogen to oil. The subcritical propagation distance, propagation duration, crack coalescence and excess oil pressure in the crack are determined using the fracture mechanics model together with the kinetics of kerogen-oil transformation. The propagation duration for the single crack is governed by the transformation kinetics whereas the propagation duration for the multiple collinear cracks may vary by two orders of magnitude depending on initial crack spacing. A large amount of kerogen (>90%) remains unconverted when the collinear cracks coalesce and the new, larger cracks resulting from coalescence will continue to propagate with continued kerogen-oil conversion. The excess oil pressure on the crack surfaces drops precipitously when the collinear cracks are about to coalesce, and crack propagation duration and oil pressure on the crack surfaces are strongly dependent on temperature. Citation: Jin, Z.-H., S. E. Johnson, and Z. Q. Fan (2010), Subcritical propagation and coalescence of oil-filled cracks: Getting the oil out of low-permeability source rocks, Geophys. Res. Lett., 37, L01305, doi:10.1029/2009GL041576.

Search for long-lived stopped R-hadrons decaying out-of-time with pp collisions using the ATLAS detector

An updated search is performed for gluino, top squark, or bottom squark R-hadrons that have come to rest within the ATLAS calorimeter, and decay at some later time to hadronic jets and a neutralino, using 5.0 and 22.9 fb(-1) of pp collisions at 7 and 8 TeV, respectively. Candidate decay events are triggered in selected empty bunch crossings of the LHC in order to remove pp collision backgrounds. Selections based on jet shape and muon system activity are applied to discriminate signal events from cosmic ray and beam-halo muon backgrounds. In the absence of an excess of events, improved limits are set on gluino, stop, and sbottom masses for different decays, lifetimes, and neutralino masses. With a neutralino of mass 100 GeV, the analysis excludes gluinos with mass below 832 GeV (with an expected lower limit of 731 GeV), for a gluino lifetime between 10 mu s and 1000 s in the generic R-hadron model with equal branching ratios for decays to q (q) over bar(chi) over tilde (0) and g (chi) over tilde (0). Under the same assumptions for the neutralino mass and squark lifetime, top squarks and bottom squarks in the Regge R-hadron model are excluded with masses below 379 and 344 GeV, respectively.