Some Notes on Liquid Sloshing in Compartmented Cylindrical Tanks Technical Report No. 1

Frequencies and total force response in rigid cylindrical tanks comparted into sectors by vertical walls and excited in translation to study liquid sloshin

YoeB toxin is activated during thermal stress.

Type II toxin-antitoxin (TA) modules are thought to mediate stress-responses by temporarily suppressing protein synthesis while cells redirect transcription to adapt to environmental change. Here, we show that YoeB, a ribosome-dependent mRNase toxin, is activated in Escherichia coli cells grown at elevated temperatures. YoeB activation is dependent on Lon protease, suggesting that thermal stress promotes increased degradation of the YefM antitoxin. Though YefM is efficiently degraded in response to Lon overproduction, we find that Lon antigen levels do not increase during heat shock, indicating that another mechanism accounts for temperature-induced YefM proteolysis. These observations suggest that YefM/YoeB functions in adaptation to temperature stress. However, this response is distinct from previously described models of TA function. First, YoeB mRNase activity is maintained over several hours of culture at 42°C, indicating that thermal activation is not transient. Moreover, heat-activated YoeB does not induce growth arrest nor does it suppress global protein synthesis. In fact, E. coli cells proliferate more rapidly at elevated temperatures and instantaneously accelerate their growth rate in response to acute heat shock. We propose that heat-activated YoeB may serve a quality control function, facilitating the recycling of stalled translation complexes through ribosome rescue pathways

Strategies for estimating the marine geoid from altimeter data

In processing altimeter data from a spacecraft borne altimeter to estimate the fine structure of the marine geoid, a problem is encountered. In order to describe the geoid fine structure, a large number of parameters must be employed and it is not possible to simultaneously estimate all of them. Unless the parameterization exhibits good orthogonality in the data, serious aliasing results. From simulation studies it has been found that amongst several competing parameterizations, the mean free air gravity anomaly model (i.e., Stokes' formula) exhibited promising geoid recovery characteristics. Using covariance analysis techniques, this report provides quantitative measures of the orthogonality properties associated with the above mentioned parameterization. It has been determined that a 5 deg x 5 deg area mean free air gravity anomaly can be estimated with an uncertainty of 1 mgal (40 cm undulation) provided that all free air gravity anomalies within a spherical radius of 10 arc degrees are simultaneously estimated

Strategies for estimating the marine geoid from altimeter data

Altimeter data from a spacecraft borne altimeter was processed to estimate the fine structure of the marine geoid. Simulation studies show that, among several competing parameterizations, the mean free air gravity anomaly model exhibited promising geoid recovery characteristics. Using covariance analysis techniques, quantitative measures of the orthogonality properties are investigated

Simulation of a lunar gradiometer mission

A lunar gradiometer mission involves the mounting of a gradiometer on a satellite which is in a low, polar, and circular lunar orbit. The results of a numerical simulation of the mission is presented. It is shown that if the satellite is in a 50 km orbit, 1 deg and 2 deg gravity anomalies may be estimated with accuracies of 12 mgal and 1 mgal respectively. At a 100 km altitude, 2 deg gravity anomalies can be estimated with an accuracy of 12 mgal. These results assume a rotating type gradiometer with a .1E accuracy. The results can be readily scaled to reflect another level

Optimal sizing of C-type passive filters under non-sinusoidal conditions

In the literature, much attention has been focused on power system harmonics. One of its important effects is degradation of the load power factor. In this article, a C-type filter is used for reducing harmonic distortion, improving system performance, and compensating reactive power in order to improve the load power factor while taking into account economic considerations. Optimal sizing of the C-type filter parameters based on maximization of the load power factor as an objective function is determined. The total installation cost of the C-type filter and that of the conventional shunt (single-tuned) passive filter are comparatively evaluated. Background voltage and load current harmonics are taken into account. Recommendations defined in IEEE standards 519-1992 and 18-2002 are taken as the main constraints in this study. The presented design is tested using four numerical cases taken from previous publications, and the proposed filter results are compared with those of other published techniques. The results validate that the performance of the C-type passive filter as a low-pass filter is acceptable, especially in the case of lower short-circuit capacity systems. The C-type filter may achieve the same power factor with a lower total installation cost than a single-tuned passive filter

Diagnosis for ecological intensification of maize-based smallholder farming systems in the Costa Chica, Mexico

Enhanced utilization of ecological processes for food and feed production as part of the notion of ecological intensification starts from location-specific knowledge of production constraints. A diagnostic systems approach which combined social-economic and production ecological methods at farm and field level was developed and applied to diagnose extent and causes of the perceived low productivity of maize-based smallholder systems in two communities of the Costa Chica in South West Mexico. Social-economic and production ecological surveys were applied and complemented with model-based calculations. The results demonstrated that current nutrient management of crops has promoted nutrition imbalances, resulting in K- and, less surprisingly N-limited production conditions, reflected in low yields of the major crops maize and roselle and low resource use efficiencies. Production on moderate to steep slopes was estimated to result in considerable losses of soil and organic matter. Poor crop production, lack of specific animal fodder production systems and strong dependence on animal grazing within communal areas limited recycling of nutrients through manure. In combination with low prices for the roselle cash crop, farmers are caught in a vicious cycle of cash shortage and resource decline. The production ecological findings complemented farmers opinions by providing more insight in background and extent of livelihood constraints. Changing fertilizer subsidies and rethinking animal fodder production as well as use of communal lands requires targeting both formal and informal governance structures. The methodology has broader applicability in smallholder systems in view of its low demand on capital intensive resource

Ocular Fundus Photography as an Educational Tool

The proficiency of nonophthalmologists with direct ophthalmoscopy is poor, which has prompted a search for alternative technologies to examine the ocular fundus. Although ocular fundus photography has existed for decades, its use has been traditionally restricted to ophthalmology clinical care settings and textbooks. Recent research has shown a role for nonmydriatic fundus photography in nonophthalmic settings, encouraging more widespread adoption of fundus photography technology. Recent studies have also affirmed the role of fundus photography as an adjunct or alternative to direct ophthalmoscopy in undergraduate medical education. In this review, the authors examine the use of ocular fundus photography as an educational tool and suggest future applications for this important technology. Novel applications of fundus photography as an educational tool have the potential to resurrect the dying art of funduscopy