Land Subdivision, Heterogeneity, and Declining Food Security for African Pastoralists

Pastoral livestock inhabit landscapes that are spatially heterogeneous and have forage patches that pulse in their value to animals. Mobile pastoralists have evolved movement patterns to maximize use of these ephemeral food sources. In pastoral communities across Africa, changes in land tenure policy and socioeconomic pressures have caused pastoralists to decrease their mobility. Pastoralists recognize that shrinking access to land reduces their options to find forage, and theory suggests that the capacity of land to support herbivores decreases as a power of the square root of area accessible. We used ecosystem modelling in South Africa and Kenya to quantify declines in the number of livestock that can be supported under subdivision

Factors Related to Marketing Successes for Fibre Producers in Middle Asia

Following the collapse of the Soviet Union in the early 1990s, the economic well-being of livestock producers of Kazakhstan and Kyrgyzstan declined dramatically (see Kerven 2003; Kerven et al., 2003). Like the economies in general, the livestock economies are slowly recovering and restructuring. Livestock producers have been encouraged by international market prices to raise sheep, goats, camels, and animals producing specialty fibre. Fine-fibre sheep and goats remain in Kazakhstan and Kyrgyzstan, but marketing of fibres from the region is not ideal. As examples, sheep pelts are not sorted and graded, which is expected by international buyers, and cashmere is shorn and sold in bulk. Lastly, marketing opportunities are limited, technology, transportation infrastructure, and market information is lacking, and the bargaining power of individual fibre producers is weak. Under support from the U.S. AID Global Livestock-Collaborative Research Support Program (GL-CRSP) project, Developing institutions and capacity for sheep and fibre marketing in Central Asia, we seek to understand the spatial relationships that can help determine success in fibre marketing

Ionic mobilities in selected fused salt systems

Transport numbers were determined in the pure fused salts, LiNO3, NaNO3, KNO3, and AgNO3 by measuring the volume changes of the material in the electrode compartments which took place during electrolysis of the melt. Transport numbers in the two binary fused salt systems AgNO3-NaNO3 and AgNO3- KNO3 were determined by measuring the volume changes accompanying electrolysis and the concentration changes accompanying electrolysis

Production Strategies of Livestock Herders in the Grasslands of Kazakhstan: Implications for the Marketing of Fine Fibres

Goat populations have been rising in Kazakhstan over the past ten years since independence and goats are preferred by farmers trying to restock. Quality of cashmere production is the key to profitable and sustainable sales to world markets for this luxury good. However, Kazakhstan did not develop a cashmere industry in the Soviet period so today goats are sheared rather than combed and little profit is made from cashmere. Goats, as well as sheep and camels are currently multi-purpose animals providing income from sales of animals, cashmere, milk and meat. This will change as the terms of trade change for high quality cashmere and households comb for fine down

Sub-lunar Tap-Yielding eXplorer, STYX

To diversify the idea pool that NASA has to draw from for future manned and unmanned missions to the Moon and Mars, a design/build competition has been posed to collegiate teams across the country. The challenge is to reach, extract, and purify underground ice reserves in a setting analogous to mars. Along the way, teams will be collecting telemetry to mimic prospecting objectives on the moon. The Sublunar Tap-Yielding eXplorer, STYX, is the team’s proposed design for the 2020 NASA RASC-AL competition. Some novel design features STYX will use are a rotary tool changer with swappable tools, a sleeve driving mode, and a pivoting heating probe. The STYX drill head will translate on two axes, use a rotary hammer drill to bore holes, sleeve boreholes with pipe to prevent collapse, and deliver water via a peristaltic pump and a two stage filtration system. Several of these design elements are innovative and conceptually proven through preliminary testing. These efforts are expected to net increased performance and differentiate STYX from other prototype submissions

The first Frontier Fields cluster: 4.5{\mu}m excess in a z~8 galaxy candidate in Abell 2744

We present in this letter the first analysis of a z~8 galaxy candidate found in the Hubble and Spitzer imaging data of Abell 2744, as part of the Hubble Frontier Fields legacy program. We applied the most commonly-used methods to select exceptionally high-z galaxies by combining non-detection and color-criteria using seven HST bands. We used GALFIT on IRAC images for fitting and subtracting contamination of bright nearby sources. The physical properties have been inferred from SED-fitting using templates with and without nebular emission. This letter is focussed on the brightest candidate we found (m$_{F160W}$=26.2) over the 4.9 arcmin$^2$ field of view covered by the WFC3. It shows a non-detection in the ACS bands and at 3.6{\mu}m whereas it is clearly detected at 4.5{\mu}m with rather similar depths. This break in the IRAC data could be explained by strong [OIII]+H{\beta} lines at z~8 which contribute to the 4.5{\mu}m photometry. The best photo-z is found at z~8.0$^{+0.2}_{-0.5}$, although solutions at low-redshift (z~1.9) cannot be completely excluded, but they are strongly disfavoured by the SED-fitting work. The amplification factor is relatively small at {\mu}=1.49$\pm$0.02. The Star Formation Rate in this object is ranging from 8 to 60 Mo/yr, the stellar mass is in the order of M$_{\star}$=(2.5-10) x 10$^{9}$Mo and the size is r~0.35$\pm$0.15 kpc. This object is one of the first z~8 LBG candidates showing a clear break between 3.6{\mu}m and 4.5{\mu}m which is consistent with the IRAC properties of the first spectroscopically confirmed galaxy at a similar redshift. Due to its brightness, the redshift of this object could potentially be confirmed by near infrared spectroscopy with current 8-10m telescopes. The nature of this candidate will be revealed in the coming months with the arrival of new ACS and Spitzer data, increasing the depth at optical and near-IR wavelengths.Comment: 4 pages, 2 figures, Accepted for publication in Astronomy and Astrophysics Letter

Grasses continue to trump trees at soil carbon sequestration following herbivore exclusion in a semiarid African savanna

Although studies have shown that mammalian herbivores often limit aboveground carbon storage in savannas, their effects on belowground soil carbon storage remain unclear. Using three sets of long‐term, large herbivore exclosures with paired controls, we asked how almost two decades of herbivore removal from a semiarid savanna in Laikipia, Kenya affected aboveground (woody and grass) and belowground soil carbon sequestration, and determined the major source (C3 vs. C4) of belowground carbon sequestered in soils with and without herbivores present. Large herbivore exclusion, which included a diverse community of grazers, browsers, and mixed‐feeding ungulates, resulted in significant increases in grass cover (~22%), woody basal area (~8 m2/ha), and woody canopy cover (31%), translating to a ~8.5 t/ha increase in aboveground carbon over two decades. Herbivore exclusion also led to a 54% increase (20.5 t/ha) in total soil carbon to 30‐cm depth, with ~71% of this derived from C4 grasses (vs. ~76% with herbivores present) despite substantial increases in woody cover. We attribute this continued high contribution of C4 grasses to soil C sequestration to the reduced offtake of grass biomass with herbivore exclusion together with the facilitative influence of open sparse woody canopies (e.g., Acacia spp.) on grass cover and productivity in this semiarid system

The Circumnuclear Molecular Gas in the Seyfert Galaxy NGC4945

We have mapped the central region of NGC 4945 in the $J=2\to1$ transition of $^{12}$CO, $^{13}$CO, and C$^{18}$O, as well as the continuum at 1.3 mm, at an angular resolution of 5\farc \times 3\farc with the Submillimeter Array. The relative proximity of NGC 4945 (distance of only 3.8 Mpc) permits a detailed study of the circumnuclear molecular gas and dust in a galaxy exhibiting both an AGN (classified as a Seyfert 2) and a circumnuclear starburst in an inclined ring with radius $\sim$2\farcs5 ($\sim$50 pc). We find that all three molecular lines trace an inclined rotating disk with major axis aligned with that of the starburst ring and large-scale galactic disk, and which exhibits solid-body rotation within a radius of $\sim$5\farc ($\sim$95 pc). We infer an inclination for the nuclear disk of $62^{\circ} \pm 2^{\circ}$, somewhat smaller than the inclination of the large-scale galactic disk of $\sim$$78^{\circ}$. The continuum emission at 1.3 mm also extends beyond the starburst ring, and is dominated by thermal emission from dust. If it traces the same dust emitting in the far-infrared, then the bulk of this dust must be heated by star-formation activity rather than the AGN. We discover a kinematically-decoupled component at the center of the disk with a radius smaller than 1\farcs4 (27 pc), but which spans approximately the same range of velocities as the surrounding disk. This component has a higher density than its surroundings, and is a promising candidate for the circumnuclear molecular torus invoked by AGN unification models.Comment: 13 pages, 10 figures,accepted by Ap

A Learning Curve Model Accounting for the Flattening Effect in Production Cycles

We investigate production cost estimates to identify and model modifications to a prescribed learning curve. Our new model examines the learning rate as a decreasing function over time as opposed to a constant rate that is frequently used. The purpose of this research is to determine whether a new learning curve model could be implemented to reduce the error in cost estimates for production processes. A new model was created that mathematically allows for a “flattening effect,” which typically occurs later in the production process. This model was then compared to Wright’s learning curve, which is a popular method used by many organizations today. The results showed a statistically significant reduction in error through the measurement of the two error terms, Sum of Squared Errors and Mean Absolute Percentage Error