The implications of stakeholders' perceptions of land for sustainable land use management in NE Ghana

There are negative implications of changes in stakeholders traditional land perceptions for sustainable land use and management in north-east Ghana. In African tenurial systems, land use was based on a local mystical view of the environment and stakeholders broad-based knowledge of the local environments. These led to sustainable resource use and management. However, in the context of current political ecology of north-east Ghana as induced by increased population growth, urbanisation, the market economy, changes in religious beliefs, and government land policies, stakeholders understandings of land have acquired even greater importance in issues of sustainable land resource use and management. A mixed methodological approach, combining both qualitative and quantitative data gathering techniques for information on stakeholders land perceptions, was used to analyse their implications for sustainable land use and management. Changes in the dynamics of stakeholders perceptions of land are partly responsible for the current state of land and environmental degradation in north-east Ghana. Policies aimed at ensuring sustainable land use and environmental management must focus on those traditional land perceptions, which encourage environmental sustainabilit

Letter from Robert Ridgway to John Muir, 1913 May 15.

3447 Oakwood Terrace, N.W.Washington, D.C.May 15, 1913.Dear Mr. Muir:I thank you very much for your kind letter of the 5th inst., which is appreciated beyond my ability to express.It does not seem possible that fourteen years have rolled by since we were together as members of the Harriman Alaska Expedition. Surely time flies more swift as we grow older.Great was my disappointment when, on returning to Washington from a visit to Illinois to find that I had missed seeing you. You were then about to start on a trip to South Ameria, I believe. I hope that you had a enjoyable trip, and saw many wonderous things that were new to you. Have you ever pub=05447 [in margin: Robert Ridgway]published anything concerning your trip? If you have please tell we where I can find it.Returning to the subject of the Harriman Alaska Expedition: Mrs Harriman sent me a copy of your memorial of Mr. Harriman, which I enjoyed reading. It has always been a source of regret to me that I could not get better acquainted with him, or at least I was so impressed. Perhaps he did not care to cultivate my acquaintance. I do not know. However it may be, I had, and still have, the greatest respect for him, and sincerely admired his executive ability, of which we had many evidences during our memorial trip.Hoping you are quite well, I am, with kind regards,Sincerely yoursRobert Ridgway

Letter from Robert Ridgway to John Muir, 1899 Aug 23.

Brookland, D.C.August 23, 1899.Dear Mr. Muir:Since my return home I have been so busy with various urgent matters that I have not yet had time to print and mount all of the tree views (Wabash Valley) which I am going to send you, and, owing to repairs in the building where my office is located I have not been able to get at the pamphlets on trees that I mention to you. I shall not forget them, however, & will get them all off to you soon as prac-02608 2ticable.Your paper on Sequoia gigantea was received yesterday. I thank you very much for it, and shall read it with great pleasure, and, I am sure, profit also.For the last week I have been wishing one of your glaciers was located somewhere in this vicinity! It has been hot as [illegible] (90° to 96° in shade) with [illegible] saturated with humidity. This is the first really wet summer in about 11 years, and has rained at least twice a week all summer - heavy rains, too; more than36 inches of rain in July and 4 inches for first half of August.Hoping you are well, I am, with best regardsSincerely yoursRobert RidgwayMr. John MuirMartinezCaliforniaPlease remember me to Mr. Keeler should you see him. - R.R

Topological Optimization of the Evaluation of Finite Element Matrices

We present a topological framework for finding low-flop algorithms for evaluating element stiffness matrices associated with multilinear forms for finite element methods posed over straight-sided affine domains. This framework relies on phrasing the computation on each element as the contraction of each collection of reference element tensors with an element-specific geometric tensor. We then present a new concept of complexity-reducing relations that serve as distance relations between these reference element tensors. This notion sets up a graph-theoretic context in which we may find an optimized algorithm by computing a minimum spanning tree. We present experimental results for some common multilinear forms showing significant reductions in operation count and also discuss some efficient algorithms for building the graph we use for the optimization

Exoplanets imaging with a Phase-Induced Amplitude Apodization Coronagraph - I. Principle

Using 2 aspheric mirrors, it is possible to apodize a telescope beam without losing light or angular resolution: the output beam is produced by ``remapping'' the entrance beam to produce the desired light intensity distribution in a new pupil. We present the Phase-Induced Amplitude Apodization Coronagraph (PIAAC) concept, which uses this technique, and we show that it allows efficient direct imaging of extrasolar terrestrial planets with a small-size telescope in space. The suitability of the PIAAC for exoplanet imaging is due to a unique combination of achromaticity, small inner working angle (about 1.5 $\lambda/d$), high throughput, high angular resolution and large field of view. 3D geometrical raytracing is used to investigate the off-axis aberrations of PIAAC configurations, and show that a field of view of more than 100 $\lambda/d$ in radius is available thanks to the correcting optics of the PIAAC. Angular diameter of the star and tip-tilt errors can be compensated for by slightly increasing the size of the occulting mask in the focal plane, with minimal impact on the system performance. Earth-size planets at 10 pc can be detected in less than 30s with a 4m telescope. Wavefront quality requirements are similar to classical techniques.Comment: 35 pages, 16 figures, Accepted for publication in Ap

Biochemical characterization and chemical inhibition o PfATP4-associated Na+-ATPase activity in Plasmodium falciparum membranes

The antimalarial activity of chemically diverse compounds, including the clinical candidate cipargamin, has been linked to the ATPase PfATP4 in the malaria-causing parasite Plasmodium falciparum. The characterization of PfATP4 has been hampered by the inability thus far to achieve its functional expression in a heterologous system. Here, we optimized a membrane ATPase assay to probe the function of PfATP4 and its chemical sensitivity. We found that cipargamin inhibited the Na+-dependent ATPase activity present in P. falciparum membranes from WT parasites and that its potency was reduced in cipargamin-resistant PfATP4-mutant parasites. The cipargamin-sensitive fraction of membrane ATPase activity was inhibited by all 28 of the compounds in the "Malaria Box" shown previously to disrupt ion regulation in P. falciparum in a cipargamin-like manner. This is consistent with PfATP4 being the direct target of these compounds. Characterization of the cipargamin-sensitive ATPase activity yielded data consistent with PfATP4 being a Na+ transporter that is sensitive to physiologically relevant perturbations of pH, but not of [K+] or [Ce2+]. With an apparent K-m for ATP of 0.2 mm and an apparent K-m for Na+ of 16 -17 mm, the protein is predicted to operate at below its half-maximal rate under normal physiological conditions, allowing the rate of Na+ efflux to increase in response to an increase in cytosolic [Na+]. In membranes from a cipargamin-resistant PfATP4-mutant line, the apparent K-m for Na+ is slightly elevated. Our study provides new insights into the biochemical properties and chemical sensitivity of an important new antimalarial drug target.This work was supported by an Australian Research Council Discovery Early Career Researcher Award (DE160101035 to A. M. L.), an Australian Research Council Linkage Project Grant (LP150101226 to K. K.), and a National Health and Medical Research Council Project Grant (1042272 to K. K.). The authors declare that they have no conflicts of interest with the contents of this article

Hydrogenated atmospheres of lava planets: atmospheric structure and emission spectra

Hot rocky super-Earths are thought to be sufficiently irradiated by their host star to melt their surface and thus allow for long-lasting magma oceans. Some processes have been proposed for such planets to have retained primordial hydrogen captured during their formation while moving inward in the planetary system. The new generation of space telescopes such as the JWST may provide observations precise enough to characterize the atmospheres and perhaps the interiors of such exoplanets. We use a vaporization model that calculates the gas-liquid equilibrium between the atmosphere (including hydrogen) and the magma ocean, to compute the elemental composition of a variety of atmospheres for different quantities of hydrogen. The elemental composition is then used in a steady-state atmospheric model to compute the atmospheric structure and generate synthetic emission spectra. With this method, we confirm previous results showing that silicate atmospheres exhibit a thermal inversion, with notably an emission peak of SiO at 9~$\mu m$. We compare our method to the literature on the inclusion of hydrogen in the atmosphere, and show hydrogen reduces the thermal inversion, because of the formation of H2O which has a strong greenhouse potential. However planets that are significantly irradiated by their host star are sufficiently hot to dissociate H2O and thus also maintain a thermal inversion. The observational implications are twofold: 1) H2O is more likely to be detected in colder atmospheres; 2) Detecting a thermal inversion in hotter atmospheres does not a priori exclude the presence of H (in its atomic form). Due to the impact of H on the overall chemistry and atmospheric structure, and therefore observations, we emphasize the importance of including volatiles in the calculation of the gas-liquid equilibrium. Finally, we provide a criterion to determine potential targets for observation.Comment: 22 pages, 17 figures + 12 figures in appendices. Accepted for publication in Astronomy & Astrophysic

MODIS Science Algorithms and Data Systems Lessons Learned

For almost 10 years, standard global products from NASA's Earth Observing System s (EOS) two Moderate Resolution Imaging Spectroradiometer (MODIS) sensors are being used world-wide for earth science research and applications. This paper discusses the lessons learned in developing the science algorithms and the data systems needed to produce these high quality data products for the earth sciences community. Strong science team leadership and communication, an evolvable and scalable data system, and central coordination of QA and validation activities enabled the data system to grow by two orders of magnitude from the initial at-launch system to the current system able to reprocess data from both the Terra and Aqua missions in less than a year. Many of the lessons learned from MODIS are already being applied to follow-on missions

High-Resolution Infrared Spectroscopy of the Brown Dwarf Epsilon Indi Ba

We report on the analysis of high-resolution infrared spectra of the newly discovered brown dwarf Epsilon Indi Ba. This is the closest known brown dwarf to the solar system, with a distance of 3.626 pc. Spectra covering the ranges of 2.308-2.317 microns and 1.553-1.559 microns were observed at a spectral resolution of R=50,000 with the Phoenix spectrometer on the Gemini South telescope. The physical paramters of effective temperature and surface gravity are derived by comparison to model spectra calculated from atmospheres computed using unified cloudy models. An accurate projected rotational velocity is also derived.Comment: 9 pages, 3 figures. Astrophysical Journal Letters, in pres