POPULATION AND LAND DEGRADATION

In this paper, we argue that there exist no significant direct links between human populations and their environments and that the intervening processes create the context within which land degradation occurs. We examine some of the intermediate mechanisms through which mounting demographic pressure leads to soil erosion and the depletion of soil fertility. The focus of attention is on set of variables defined in this paper as the structure of landholding (size of holdings, fragmentation/ dispersion, fragility, tenure, etc.). How demographically-induced changes in the structure of land-holding affect land management strategies (investments and land use) is key to understanding land degradation. Traditional perspectives on population and agricultural intensification, such as those developed by Malthus and Boserup, are incomplete at best. This is because they fail to fully incorporate the intermediate linkages both to and from the changing structure of landholding. As a result, avenues for policy research and intervention have been limited. On the population side, the answer has been to control growth (mostly through family planning). On the natural resources side, the thrust has been the dissemination of resource-saving technologies. The paper concludes with a discussion of the implications of this review for future research and policy action.Land Economics/Use,

Using pen Source Data Inputs to Map Food Insecurity in Cumberland County, Maine

In 2010, Mapping Food Insecurity’s Project Director (PD) participated in “The Campaign to Promote Food Security in Cumberland County, Maine.” The Campaign drew together a 60 member coalition to address rapidly increasing food insecurity challenges in the county. It produced a report with a series of recommendations grouped under six strategic community goals. One of the recommendations called for the use of ‘mapping and connectivity software to determine location of vulnerable populations and services in order to plan best future delivery and use of food access services in Cumberland Count

THIS CITY IS A CLOCK

This dissertation includes a novel, This City is a Clock, and a critical introduction, “Technologies of the Novel.” This City is a Clock charts the construction of Edinburgh’s New Town and the development of the Scottish Enlightenment. The protagonist is a boy when the novel begins and has grown to old age by the final pages. As a child, he is put to work by the architects of the new town when they discover that he has unusual mathematical gifts. To them, his strange talent seems an emblem of the new rational order they are hoping to create. And the boy is eager to help them: he wants to be able to escape his impoverished background. His family is so poor that they live next door to a witch, and she terrifies him. However, the architects repeatedly run into trouble, their goals being opposed by a variety of vested interests in the city, and the boy discovers that the only way he can overcome these troubles is to go to the witch and ask for her advice. But each time she offers to help, the cost to him and the rest of the city grows. “Technologies of the Novel” explores questions of craft, inter-generational artistic anxiety, and the development of the Anglophone novel over time

Surgery description of colored knots

By a knot, or link, we mean a circle, or a collection of circles, embedded in the three-sphere S3. The study of knots is a very rich subject and plays a key role in the area of low-dimensional topology. In fact, a theorem of W.B.R. Lickorish and A.D. Wallace states that any three-dimensional manifold may be described by Dehn surgery along a link which is the process of removing the link from S3 and then gluing it back in a way that possibly changes the resulting manifold. In this dissertation, we will be interested in the pair (K, ρ) consisting of a knot K and a surjective map ρ from the knot group onto a dihedral group of order 2p called a coloring. Such an object is said to be a p-colored knot. In Surgery untying of colored knots , D. Moskovich conjectures that for any odd prime p there are exactly p equivalence classes of p-colored knots up to surgery which preserves colorability. This is an analog to the classical result that every knot has a surgery description or equivalently that every knot is surgery equivalent to the unknot if we place fewer restrictions on the allowed surgery curves. We show that there are at most 2p equivalence classes for p any odd number. This is an improvement upon the previous results by Moskovich for p = 3, and 5, with no upper bound given in general. We do this by defining a new invariant, or an algebraic object associated to a p-colored knot, which is complete in the sense that two p-colored knots are surgery equivalent if and only if they both have the same value of this invariant. The complete invariant consists of Moskovich’s colored untying invariant redefined in the same way as the three-manifold invariants developed by T. Cochran, A. Gerges, and K. Orr, and another object we call the η invariant. We also extend these methods to give similar results for A4-colored knots which have representations onto the alternating group on four letters

Concurrent Multipath Transfer: Scheduling, Modelling, and Congestion Window Management

Known as smartphones, multihomed devices like the iPhone and BlackBerry can simultaneously connect to Wi-Fi and 4G LTE networks. Unfortunately, due to the architectural constraints of standard transport layer protocols like the transmission control protocol (TCP), an Internet application (e.g., a file transfer) can use only one access network at a time. Due to recent developments, however, concurrent multipath transfer (CMT) using the stream control transmission protocol (SCTP) can enable multihomed devices to exploit additional network resources for transport layer communications. In this thesis we explore a variety of techniques aimed at CMT and multihomed devices, such as: packet scheduling, transport layer modelling, and resource management. Some of our accomplishments include, but are not limited to: enhanced performance of CMT under delay-based disparity, a tractable framework for modelling the throughput of CMT, a comparison of modelling techniques for SCTP, a new congestion window update policy for CMT, and efficient use of system resources through optimization. Since the demand for a better communications system is always on the horizon, it is our goal to further the research and inspire others to embrace CMT as a viable network architecture; in hopes that someday CMT will become a standard part of smartphone technology

An Investigation Of Six Poorly Described Close Visual Double Stars Using Speckle Interferometry

Continued observation of double stars is necessary for confirmation of binarity and to provide updates to astrometric data used to compute accurate binary orbital parameters, thereby more accurately informing stellar mass estimations – the critical parameter from which stellar models are derived. In October of 2013, six double stars from the Washington Double Star (WDS) catalog exhibiting close separations, as well as significant deviations from previously published orbits, were observed and imaged using the speckle interferometric technique on the 2.1-meter telescope at Kitt Peak National Observatory (KPNO) in Arizona. The observations of the six double stars occurred as part of large, collaborative, eight-night, student-learning-centered observing run organized by principal investigator Genet of California Polytechnic Institute. The run produced in total roughly 1000 raw speckle images for each of the more than 1000 double stars and single reference stars observed, resulting in a total database of 1.4 terabytes. The speckle images for the targets, including the six targets investigated in this thesis, were taken using a relatively low-cost, portable speckle interferometry camera system developed by Genet, the heart of which is a lightweight, high speed, high signal to noise ratio (SNR) Andor electron multiplying CCD (EMCCD) camera capable of exposures on the order of tens of milliseconds. Exposures of 10-20 milliseconds are faster than atmospheric coherence timescales, and allow for the implementation of the speckle interferometry – the obtainment of diffraction-limited image information of binary stars defined by the full aperture of the telescope from the autocorrelation and Fourier analysis of randomly distributed, isoplanatically correlated speckle pairs, which represent the diffraction-limited images of the associated coherence cells above and within the atmospheric area of the primary aperture (sub-apertures). Following the Oct. 2013 observing run, reduction and analysis of the speckle images for the six target binary stars (as well as five calibration binaries) and determination of the new astrometry was completed using the general purpose astrometry software program PlateSolve3 (PS3), written and developed by Rowe & Genet (2014). Using the new astrometric data derived from the Oct. 2013 2.1-meter speckle observations, the previously published United States Naval Observatory (USNO) orbital plots for the six target doubles were updated to reflect the new, and in some cases missing measurements. Target double star orbits were reevaluated in light of the updates in order to draw conclusions about the characteristics of each proposed binary system. In all six target cases, continued trends in significant astrometric deviations from published orbits and ephemerides have been demonstrated by the new observations, indicating the need for orbital revisions of these binaries. Analysis of systems WDS22357+5413, WDS02231+7021, and WDS06256+2227 indicate rectilinear rather than Keplerian motion, and are concluded to likely be optical doubles. As a result of this work, two observations of WDS05153+4710 were shown to be erroneous and have been scheduled to be removed from this binary’s WDS observational record (Mason, private communication, 2015). Complementary to the central goal of investigating the six target close visual double stars via speckle interferometry, the entire effort demonstrated the applicability and utilization of relatively low-cost portable speckle camera systems on large telescopes, as well as the value and advantages of student participation and contribution within the realm of a large-scale observing run at a major observatory and the resulting peer reviewed scientific works that follow

Detrital Zircon Evidence for Mixing of Mazatzal Province Age Detritus With Yavapai Age (ca. 1700-1740 Ma) and Older Detritus in the ca. 1650 Ma Mazatzal Province of Central New Mexico, USA

Preliminary detrital zircon age distributions from Mazatzal crustal province quartzite and schist exposed in the Manzano Mountains and Pedernal Hills of central New Mexico are consistent with a mixture of detritus from Mazatzal age (ca. 1650 Ma), Yavapai age (ca. 1720 Ma.), and older sources. A quartzite sample from the Blue Springs Formation in the Manzano Mountains yielding 67 concordant grain analyses shows two dominant age peaks of 1737 Ma and 1791 Ma with a minimum peak age of 1652 Ma. Quartzite and micaceous quartzite samples from near Pedernal Peak give unimodal peak ages of ca. 1695 Ma and 1738 Ma with minimum detrital zircon ages of ca. 1625 Ma and 1680 Ma, respectively. A schist sample from the southern exposures of the Pedernal Hills area gives a unimodal peak age of 1680 Ma with a minimum age of ca. 1635 Ma. Minor amounts of older detritus (\u3e1800 Ma) possibly reflect Trans-Hudson, Wyoming, Mojave Province, and older Archean sources and aid in locating potential source terrains for these detrital zircon. The Blue Springs Formation metarhyolite from near the top of the Proterozoic section in the Manzano Mountains yields 71 concordant grains that show a preliminary U-Pb zircon crystallization age of 1621 ¿ 5 Ma, which provides a minimum age constraint for deposition in the Manzano Mountains. Normalized probability plots from this study are similar to previously reported age distributions in the Burro and San Andres Mountains in southern New Mexico and suggest that Yavapai Province age detritus was deposited and intermingled with Mazatzal Province age detritus across much of the Mazatzal crustal province in New Mexico. This data shows that the tectonic evolution of southwestern Laurentia is associated with multiple orogenic events. Regional metamorphism and deformation in the area must postdate the Mazatzal Orogeny and ca. 1610 Ma ¿ 1620 Ma rhyolite crystallization and is attributed to the Mesoproterozoic ca. 1400 ¿ 1480 Ma Picuris Orogeny