2,563 research outputs found
Defining a New Ethical Standard for Human in Vitro Embryos in the Context of Stem Cell Research
This iBrief discusses some of the social, ethical and legal considerations surrounding the use of unimplanted, in vitro embryos in stem cell research. It proposes that a new ethical standard be elucidated for these embryos. The iBrief gives an overview of two proposals for such a standard at opposite ends of the spectrum: treating the in vitro embryo as a legal person versus treating it as mere property. It argues against both approaches. The former can have undesirable social implications including undue interference with female reproductive autonomy, while the latter would objectify potential human life and reproductive potential. The iBrief proposes an intermediate approach that treats the embryo as a special entity. It warns against a model whereby the respect accorded to embryos is made dependent on the attainment of various qualitative or developmental criteria. The complexities surrounding human life, it argues, are too uncertain. What is certain is the embryo\u27s unique potential for human life, at any developmental stage. This, the iBrief proposes, should be the sole criterion for an embryo\u27s special status, a status that should be confined within constitutional limits
Determinants of Selected Agricultural Export Crops in Nigeria: An Ecm Approach
This study examines the factors that determine the export performance of three major agricultural exportable commodities of cocoa, rubber and palm-kernel in the context of liberalization. Using time series data covering thirty three years and to avoid spurious result, error correction model was applied in the analysis. The unit root test is in line with the a priori expectation that macroeconomic variables are not stationary at their level. Virtually all the variables tested were differenced once before attaining stationarity. Each of the three equations indicated that the dependent variables cointegrated with their arguments at 1 percent level. There is the existence of short term and long term equilibrium relationships between the dependent variables and their determinants. The results of the parsimonious error correction specifications showed that the previous yearâs output and the net value of world trade negatively affect cocoa exports at 1 percent level while the previous yearâs GDP positively contributes to cocoa exports at 5 percent. The lagged price ratio reduces rubber exports significantly at 5 percent but the real exchange rate significantly increases the export performance of rubber at 10 percent level. The previous yearâs exports of palm kernel and the real GDP contributed positively to palm-kernel exports at 5 percent level while the lagged premium and palm kernel output negatively contributed to its export at 5 percent and 10 percent respectively. Promotion of agricultural exports is essential to reduce the burden of dependence on oil exportsAgricultural exports, Cointegration, ECM, Nigeria, Agricultural and Food Policy, Community/Rural/Urban Development, Crop Production/Industries, Demand and Price Analysis, Farm Management, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Industrial Organization, International Relations/Trade, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,
C1-continuous space-time discretization based on Hamilton's law of varying action
We develop a class of C1-continuous time integration methods that are
applicable to conservative problems in elastodynamics. These methods are based
on Hamilton's law of varying action. From the action of the continuous system
we derive a spatially and temporally weak form of the governing equilibrium
equations. This expression is first discretized in space, considering standard
finite elements. The resulting system is then discretized in time,
approximating the displacement by piecewise cubic Hermite shape functions.
Within the time domain we thus achieve C1-continuity for the displacement field
and C0-continuity for the velocity field. From the discrete virtual action we
finally construct a class of one-step schemes. These methods are examined both
analytically and numerically. Here, we study both linear and nonlinear systems
as well as inherently continuous and discrete structures. In the numerical
examples we focus on one-dimensional applications. The provided theory,
however, is general and valid also for problems in 2D or 3D. We show that the
most favorable candidate -- denoted as p2-scheme -- converges with order four.
Thus, especially if high accuracy of the numerical solution is required, this
scheme can be more efficient than methods of lower order. It further exhibits,
for linear simple problems, properties similar to variational integrators, such
as symplecticity. While it remains to be investigated whether symplecticity
holds for arbitrary systems, all our numerical results show an excellent
long-term energy behavior.Comment: slightly condensed the manuscript, added references, numerical
results unchange
Nicotinamide Riboside and the Aortic Response to Angiotensin II Infusion in Mice
Damage to vascular cells of the aorta drives vascular dysfunction and disease. Nicotinamide adenine dinucleotide (NAD+) is a cellular metabolite critical to cellular health, but NAD+ levels decline during oxidative insults and aging. The NAD+ precursor, nicotinamide riboside (NR) can augment NAD+ levels. Herein, I determined whether orally administrated NR could protect the aorta of middle-aged mice from acute and sustained angiotensin II (Ang II) infusion-induced damage. I demonstrate that orally administered NR can protect the aorta from damage imposed by Ang II
Improving optimal control of grid-connected lithium-ion batteries through more accurate battery and degradation modelling
The increased deployment of intermittent renewable energy generators opens up
opportunities for grid-connected energy storage. Batteries offer significant
flexibility but are relatively expensive at present. Battery lifetime is a key
factor in the business case, and it depends on usage, but most techno-economic
analyses do not account for this. For the first time, this paper quantifies the
annual benefits of grid-connected batteries including realistic physical
dynamics and nonlinear electrochemical degradation. Three lithium-ion battery
models of increasing realism are formulated, and the predicted degradation of
each is compared with a large-scale experimental degradation data set
(Mat4Bat). A respective improvement in RMS capacity prediction error from 11\%
to 5\% is found by increasing the model accuracy. The three models are then
used within an optimal control algorithm to perform price arbitrage over one
year, including degradation. Results show that the revenue can be increased
substantially while degradation can be reduced by using more realistic models.
The estimated best case profit using a sophisticated model is a 175%
improvement compared with the simplest model. This illustrates that using a
simplistic battery model in a techno-economic assessment of grid-connected
batteries might substantially underestimate the business case and lead to
erroneous conclusions
Evaluasi Bahaya Gempa (Seismic Hazard) Dengan Menggunakan Metode Point Source Dan Penentuan Respons Spektra Desain Kota Kupang
The earthquake which occurred at a site is caused by the release of energy from theepicenter, which then propagate to the location of the earthquake. The amount of energy tothe location will affect the magnitude earthquake that occurred. Seismic hazard analysis is ananalysis of the influence of the release of energy from the epicenter of a particular location,which will result in ground motion parameters are useful for the design of the structure.Based on Standar Perencanaan Ketahanan Gempa untuk Struktur Bangunan Gedung(ISO - 1726 - 2002), the city of Kupang located within the boundary 4 with 0,20 g seismicresponse factor and region 5 with 0.25g earthquake response factor. However, within recentyears, occurred several times a quake with a magnitude of more than 8 on the Richter scale.Therefore, the need to do research on Seismic Hazard and determination of response spectradesign of the city of Kupang in order to know the value of Peak Ground Acceleration (PGA)*) Dosen Teknik Sipil FST Undana 42Kupang earthquake return period of 500 years and the response spectra for the city ofKupang.This research results an earthquake with return period of 500 years in Kupang city has aPeak Ground Acceleration (PGA), 0.2 g and has a duration of between 8 seconds and theresponse spectra for Kupang by using the maximum acceleration is 1961.33 mm/s2
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