Applying Optimization to the Conservation Project Selection Process: A Case Study of Readiness and Environmental Protection Initiative

This study presents a thorough discussion of the efficiency and effectiveness improvement from optimization models (Binary Linear Programming and Goal Programming), as applied to the Department of Defense’s Readiness and Environmental Protection Initiative. The OM models can yield 21% and 19.1% higher benefit scores respectively, spending $13,013,473 and$31,463,473 less total acquisition costs. To achieve the same level of conservation benefits for the current rank based approach, the REPI would spend additional $20.1 million and approximate 50% of the budget. A counterpart of OM- the cost-effective analysis is observed to be inefficient when the problem becomes complex. In a real world of political environment of the conservation programs, we suggest a hybrid method of current rank based approach and the OM as well as the GP to address incompatible goals of interests groups.Environmental Economics and Policy, C6, Q24,

Early stage dental caries detection using near infrared spatial frequency domain imaging

Early stage dental caries can be remineralized without the need for “drill-and-fill” treatments that are more invasive and less permanent. However, early stage caries lesions typically present as a white spot on a white background, resulting in many lesions only being identified after they have developed beyond the point of remineralization as cavities. We present a spatial frequency domain imaging technique to characterize the optical properties of dental tissue. This technique enables different dental tissue types (healthy enamel, healthy dentin and damaged or demineralized enamel) to be easily distinguished from one another and allows quantification of the reduced scattering coefficients of dental tissue. The use of near-infrared light at 850 nm allows high depth penetration into the tissue and suppression of absorption effects, ensuring only changes in the reduced scattering coefficient that result directly from demineralization of enamel are observed and simplifying the analysis method. This technique provides a tool to both guide the attention of dentists to areas of interest and potential demineralization, and to provide longitudinal quantified assessments to monitor caries lesion behaviour over time

Survival and Home Range Estimates of Pen-Raised Northern Bobwhites in Buffer Strip and Non-Buffer Strip Habitats

We investigated the effect of agricultural buffer strips on survival and home range estimates of pen-raised northern bobwhites (Colinus virginianus) at Tudor Farms on the Eastern Shore of Maryland. In September 2000 we released groups of bobwhites into 9 buffer strip (treatment) areas and 9 non-buffer strip (control) areas among 11 agricultural farms. Each group consisted of 4 radiomarked bobwhites and 26 non-radiomarked bobwhites. To maintain contact with the established coveys, additional radiomarked bobwhites (n = 177) were introduced into the coveys as radiomarked birds died. Survival for bobwhites released in buffer strip areas was lower (P \u3c 0.001) than survival in non-buffer strip areas. None of the radiomarked bobwhites released in the buffer strip areas survived past 27 weeks, whereas 11% of radiomarked bobwhites in non-buffer strip areas survived to 27 weeks and 1 bird survived to 41 weeks. Predation was the primary mortality factor (88%), followed by unknown causes (7%), stress (2%), hunting (2%), and road kill (1%). Mean fall and winter home range (95% minimum convex polygon) for 21 bobwhite coveys was 24.2 +- 3.5 ha, ranging from 1.7 to 65.8 ha. Home range areas of bobwhite coveys in buffer strips (n = 12, x¯ +- 15.0 2.7 ha) was significantly smaller (P = 0.002) than non-buffer strip coveys (n = 9, x¯ = 36.4 +- 4.9 ha). We conclude that the smaller home ranges in buffer strip areas seem to indicate better habitat quality; however, high mortality rates of pen-raised bobwhites limited our ability to confirm this

Tunable cw UV laser with <35 kHz absolute frequency instability for precision spectroscopy of Sr Rydberg states

We present a solid-state laser system that generates over 200 mW of continuous-wave, narrowband light, tunable from 316.3 nm – 317.7 nm and 318.0 nm – 319.3 nm. The laser is based on commercially available fiber amplifiers and optical frequency doubling technology, along with sum frequency generation in a periodically poled stoichiometric lithium tantalate crystal. The laser frequency is stabilized to an atomic-referenced high finesse optical transfer cavity. Using a GPS-referenced optical frequency comb we measure a long term frequency instability of < 35 kHz for timescales between 10−3 s and 103 s. As an application we perform spectroscopy of Sr Rydberg states from n = 37 – 81, demonstrating mode-hop-free scans of 24 GHz. In a cold atomic sample we measure Doppler-limited linewidths of 350 kHz

Compressive quantum waveform estimation

Quantum waveform estimation, in which quantum sensors sample entire time series, promises to revolutionize the sensing of weak and stochastic signals, such as the biomagnetic impulses emitted by firing neurons. For long duration signals with rapid transients, regular quantum sampling becomes prohibitively resource intensive as it demands many measurements with distinct control and readout. In this Manuscript, we demonstrate how careful choice of quantum measurements, along with the modern mathematics of compressive sensing, achieves quantum waveform estimation of sparse signals in a number of measurements far below the Nyquist requirement. We sense synthesized neural-like magnetic signals with radiofrequency-dressed ultracold atoms, retrieving successful waveform estimates with as few measurements as compressive theoretical bounds guarantee.Comment: 6 pages + 3 pages of Supplemental Material, 3 figures + 1 supplemental figur

The logic of recurrent circuits in the primary visual cortex

Recurrent cortical activity sculpts visual perception by refining, amplifying or suppressing visual input. However, the rules that govern the influence of recurrent activity remain enigmatic. We used ensemble-specific two-photon optogenetics in the mouse visual cortex to isolate the impact of recurrent activity from external visual input. We found that the spatial arrangement and the visual feature preference of the stimulated ensemble and the neighboring neurons jointly determine the net effect of recurrent activity. Photoactivation of these ensembles drives suppression in all cells beyond 30 µm but uniformly drives activation in closer similarly tuned cells. In nonsimilarly tuned cells, compact, cotuned ensembles drive net suppression, while diffuse, cotuned ensembles drive activation. Computational modeling suggests that highly local recurrent excitatory connectivity and selective convergence onto inhibitory neurons explain these effects. Our findings reveal a straightforward logic in which space and feature preference of cortical ensembles determine their impact on local recurrent activity

Tritium monitoring of groundwater and surfaces

There are numerous facilities, both within the US and in the rest of the world, within the complex of radiation laboratories and production plants where tritium has been released into the environment because of historic or ongoing mission-related operations. Many of environmental restoration projects have detected low levels of tritium contamination in local streams, ponds, and/or ground water. Typically these waters are moving or have the potential to move offsite and are viewed as a potential risk to the public and environment. Los Alamos National Laboratory will modify the well-proven long-range alpha detection (LRAD) technique for detection of ionizing radiation to optimize a system for detecting tritium in groundwater and other surfaces. The LRAD technique relies on detection of ionized air molecules rather than direct detection of ionizing radiation. The detected electrical current is proportional to the number of ionized air molecules present, which is in turn a measure of the amount of contamination present. Although this technique has been used commercially to measure alpha contamination on objects and surfaces, the technique is also ideal for monitoring low-energy beta particles. The authors have demonstrated beta detection using {sup 54}Mn, {sup 14}C, {sup 147}Pm, {sup 99}Tc, {sup 90}Sr, and {sup 36}Cl sources. Thus, the detector technology and detection of beta particles using this technology have both been demonstrated. The extreme short range of tritium beta particles necessitates an optimization of the detector system. In this paper, the authors will discuss these new designs

Criticality of natural absorbing states

We study a recently introduced ladder model which undergoes a transition between an active and an infinitely degenerate absorbing phase. In some cases the critical behaviour of the model is the same as that of the branching annihilating random walk with $N\geq 2$ species both with and without hard-core interaction. We show that certain static characteristics of the so-called natural absorbing states develop power law singularities which signal the approach of the critical point. These results are also explained using random walk arguments. In addition to that we show that when dynamics of our model is considered as a minimum finding procedure, it has the best efficiency very close to the critical point.Comment: 6 page