PUZZLE - A program for computer-aided design of printed circuit artwork

Program assists in solving spacing problems encountered in printed circuit /PC/ design. It is intended to have maximum use for two-sided PC boards carrying integrated circuits, and also aids design of discrete component circuits

On the acceptance of urban beavers in Martinez, California

As ecosystem engineers, beavers construct complex riparian and wetland habitats that benefit many other species, including endangered salmonids. Through their landscape alterations, beavers also promote increased groundwater recharge and provide refugia during wildfires and high flow events by impounding water and allowing it to spread across the landscape. Prior to the North American colonial fur trapping campaigns, there were between 60 and 400 million beavers in North America. By the beginning of the 20th century, beavers were extirpated from many parts of the continent, however through human efforts, their population has since rebounded to between 10 and 15 million. The loss of beavers has significantly affected the arid west, including California where beavers had played an important role by impounding water on the surface and water on the landscape. Human tolerance of beaver behavior has been found to be one of the biggest barriers to increasing the number of beavers in California. Starting in the early 20th century, if beavers caused a disruption in human dominated areas in California, the most common action was to deprecate the animal in order to prevent potential flooding or vegetation damage. However, in the past 40 years, there has been increasing interest in coexistence alternatives where humans mitigate potential damages through various methods, allowing beavers and humans to coexist. To better understand how social factors affect the decision to coexist with beavers, I conducted a case study of a high-profile event culminating in beaver coexistence which took place from November 2007 through April 2008 in Martinez, California. This was one of the first cases in recent California history where an urban community chose to coexist with beavers rather than remove them. I reviewed documents, transcribed recordings of city council meetings, and conducted 23 semi-structured interviews with individuals who could provide insights relevant to the Martinez events, including an understanding of the factors that contributed to the community’s decision to coexist with beavers and the legacy of the Martinez decision. I thematically coded these materials for recurrent patterns and themes. Key findings included: (1) the local history and experiences of those that lived in the area contributed to a sense of place which influenced Martinez’s decision to coexist with beavers; (2) the urban location and associated easy accessibility of the beavers and dam helped foster a relationship with the beavers; and (3) coexistence is more likely to occur when people can experience wildlife through non-conflict-oriented interactions before conflicts arise

Manufacture of Fused Deposition Modeling Joints using ULTEM 9085

The manufacture of joints between a base structure and a structure manufactured via Fused Deposition Modeling (FDM) will be investigated. ULTEM 9085, a high temperature plastic with potential aerospace applications, will be the material used. The specific application this research is focused on is a robotic and mobile FDM printer capable of building structures onto other structures in space. A joint will be formed by fusing the base layer of the printed structure and the top of the base structure together. Tensile testing will be performed to determine the strength of the bond between parts. Tensile specimens will be manufactured with variable printer settings, including air gap and build volume temperature. In the orbital environment, lamps could be used to heat the part in place of a heated build volume. A thermodynamic model is used to estimate power required to heat the printed part in vacuum. In addition, tensile and compression testing will be done on parts printed in various orientations to validate material properties. The material properties of specimens manufactured under normal conditions will be the standard that printed joints will be compared against

Modern holographic recording and analysis techniques applied to edge-lit holograms and their applications

The main aim of this research was to create and analyse a compact holographic optical system which is illuminated through the edge of the substrate. Edge-lit holograms are used in order to minimize the space requirements for various possible replay geometries. Many aspects of the recording, analysing, and replay techniques were found to be very critical for creating an efficient optical system. The edge-lit holograms were recorded in a photopolymer film developed by Du Pont. When recording an interference pattern in the film with a steep reference beam, the effects of attenuation, beam ratio, and refractive index matching on optical efficiency are much more pronounced than in traditional holography due to the effective film thickness and Fresnel reflections. [Continues.

An unified timing and spectral model for the Anomalous X-ray Pulsars XTE J1810-197 and CXOU J164710.2-455216

Anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs) are two small classes of X-ray sources strongly suspected to host a magnetar, i.e. an ultra-magnetized neutron star with $B\approx 10^14-10^15 G. Many SGRs/AXPs are known to be variable, and recently the existence of genuinely "transient" magnetars was discovered. Here we present a comprehensive study of the pulse profile and spectral evolution of the two transient AXPs (TAXPs) XTE J1810-197 and CXOU J164710.2-455216. Our analysis was carried out in the framework of the twisted magnetosphere model for magnetar emission. Starting from 3D Monte Carlo simulations of the emerging spectrum, we produced a large database of synthetic pulse profiles which was fitted to observed lightcurves in different spectral bands and at different epochs. This allowed us to derive the physical parameters of the model and their evolution with time, together with the geometry of the two sources, i.e. the inclination of the line-of-sight and of the magnetic axis with respect to the rotation axis. We then fitted the (phase-averaged) spectra of the two TAXPs at different epochs using a model similar to that used to calculate the pulse profiles ntzang in XSPEC) freezing all parameters to the values obtained from the timing analysis, and leaving only the normalization free to vary. This provided acceptable fits to XMM-Newton data in all the observations we analyzed. Our results support a picture in which a limited portion of the star surface close to one of the magnetic poles is heated at the outburst onset. The subsequent evolution is driven both by the cooling/varying size of the heated cap and by a progressive untwisting of the magnetosphere.Comment: 15 pages, 12 figures, accepted for publication in Ap

Old isolated accreting neutron stars: the diffuse x-ray emission from the galactic center

The contribution of weakly--magnetized (B\sim 10^9 G) neutron stars accreting the interstellar medium to the diffuse X--ray emission observed in the Galactic Center is investigated. It is shown that, under rather conservative assumptions about the neutron stars and gas distributions, the accretion luminosity can account for a sizable fraction, possibly most, of the detected X--ray flux in the 2.5--7 keV band. In particular, model results are compared with {\it Granat\/} data and show a general agreement in both the flux energy and radial distributions

Effect of Treadmill Surface Stiffness on the Running Economy Benefits of a Highly-Cushioned Racing Shoe: A Pilot Study

Running economy (RE) is defined as the oxygen consumption (VO2) at a given running speed. The Nike Vaporfly line of racing shoes, which includes more compliant and resilient midsole foam and a carbon-fiber plate, have been shown to improve RE during treadmill testing. Previous research suggests that RE in general is worse on treadmills with stiffer running platforms. However, it is unclear if the magnitude of the RE benefits provided by these new shoes relative to a control shoe differ based on treadmill stiffness. Given that some treadmill platforms allow more flex or compliance, this may be an important consideration when comparing the effects of new footwear. Placing shims under the spans of a treadmill can increase surface stiffness and allow for such comparisons. PURPOSE: Determine the RE benefits of the Nike Vaporfly NEXT% 2 (VFN2) racing shoe relative to a mass-matched control (CTRL) shoe, under shimmed (SHIM) and non-shimmed (NON) treadmill conditions. METHODS: Four male runners (23 ± 8 years, 176 ± 4 cm, 61.8 ± 8.6 kg) completed 8 x 5-minute trials at 12 km·hr-1 on a level, motorized treadmill (Cardiac Science TM 55) with a 5-minute rest between trials. Both the VNF2 and CTRL shoe were tested twice under both the SHIM and NON treadmill conditions. The Asics Hyper Speed was used as the CTRL shoe given its traditional midsole foam and absence of a carbon-fiber plate. Approximately 16 g was added to VFN2 to mass-match the CTRL shoe. For the SHIM trials, an adjustable screw jack was elevated under both sides of the treadmill spans near the location of foot strike. VO2 was measured continuously throughout each trial and averages from the final 2-minutes for each of the two trials for a given shoe-treadmill condition were determined. RESULTS: VFN2 improved RE to a similar extent relative to CTRL for NON (1.2 ± 0.7%; p = 0.041) and for SHIM (1.1 ± 0.43%; p = 0.013) treadmill conditions. The average difference (NON minus SHIM) in the % energy savings conferred by the VFN2 was only 0.08 ± 0.29%. VO2 (ml·kg-1·min-1) is provided for each subject based on shoe-treadmill condition with % reductions in VO2 for VFN2 relative to CTRL displayed for each treadmill condition. Subject A: CTRL-NON 36.68, VFN2-NON 36.16; 1.41%; CTRL-SHIM 37.02, VFN2-SHIM 36.50; 1.40%. Subject B: CTRL-NON 37.98, VFN2-NON 37.22; 2.02%; CTRL-SHIM 37.45, VFN2-SHIM 36.88; 1.53%. Subject C: CTRL-NON 37.26, VFN2-NON 36.90; 0.98%; CTRL-SHIM 37.86, VFN2-SHIM 37.49; 0.98%. Subject D: CTRL-NON 38.41, VFN2-NON 38.26; 0.39%; CTRL-SHIM 38.43, VFN2-SHIM 38.21; 0.57%. Independent of shoe condition, SHIM resulted in worse RE for subject A and C, improved RE for subject B, and left RE unchanged for subject D. CONCLUSION: Shimming the span of the Cardiac Science TM 55 treadmill to increase surface stiffness may negatively impact RE overall for some individuals. However, this does not appear to impact the benefits provided by the VFN2 relative to a CTRL shoe at the 12 km·hr-1 speed tested in this pilot study

Recent positive selection in genes of the mammalian epidermal differentiation complex locus

The epidermal differentiation complex (EDC) is the most rapidly evolving locus in the human genome compared to that of the chimpanzee. Yet the EDC genes that are undergoing positive selection across mammals and in humans are not known. We sought to identify the positively selected genetic variants and determine the evolutionary events of the EDC using mammalian-wide and clade-specific branch- and branch-site likelihood ratio tests and a genetic algorithm (GA) branch test. Significant non-synonymous substitutions were found in filaggrin, SPRR4, LELP1, and S100A2 genes across 14 mammals. By contrast, we identified recent positive selection in SPRR4 in primates. Additionally, the GA branch test discovered lineage-specific evolution for distinct EDC genes occurring in each of the nodes in the 14-mammal phylogenetic tree. Multiple instances of positive selection for FLG, TCHHL1, SPRR4, LELP1, and S100A2 were noted among the primate branch nodes. Branch-site likelihood ratio tests further revealed positive selection in specific sites in SPRR4, LELP1, filaggrin, and repetin across 14 mammals. However, in addition to continuous evolution of SPRR4, site-specific positive selection was also found in S100A11, KPRP, SPRR1A, S100A7L2, and S100A3 in primates and filaggrin, filaggrin2, and S100A8 in great apes. Very recent human positive selection was identified in the filaggrin2 L41 site that was present in Neanderthal. Together, our results identifying recent positive selection in distinct EDC genes reveal an underappreciated evolution of epidermal skin barrier function in primates and humans