The Price of Snow: Albedo Valuation and a Case Study for Forest Management

Several climate frameworks have included the role of carbon storage in natural landscapes as a potential mechanism for climate change mitigation. This has resulted in an incentive to grow and maintain intact long-lived forest ecosystems. However, recent research has suggested that the influence of albedo-related radiative forcing can impart equal and in some cases greater magnitudes of climate mitigation compared to carbon storage in forests where snowfall is common and biomass is slow-growing. While several methodologies exist for relating albedo-associated radiative forcing to carbon storage for the analysis of the tradeoffs of these ecosystem services, they are varied, and they have yet to be contrasted in a case study with implications for future forest management. Here we utilize four methodologies for calculating a shadow price for albedo radiative forcing and apply the resulting eight prices to an ecological and economic forest model to examine the effects on optimal rotation periods on two different forest stands in the White Mountain National Forest in New Hampshire, USA. These pricing methodologies produce distinctly different shadow prices of albedo, varying from a high of 9.36 × 10−4 and a low of 1.75 × 10−5 $w−1yr−1 in the initial year, to a high of 0.019 and a low of 3.55 × 10−4$w−1yr−1 in year 200 of the simulation. When implemented in the forest model, optimal rotation periods also varied considerably, from a low of 2 to a high of 107 years for a spruce-fir stand and from 35 to 80 years for a maple-beech-birch stand. Our results suggest that the choice of climate metrics and pricing methodologies for use with forest albedo alter albedo prices considerably, may substantially adjust optimal rotation period length, and therefore may have consequences with respect to forest land cover change

Seasonal and geographic variation in the shell microstructure of a salt-marsh bivalve (Geukensia demissa (Dillwyn))

The microstructure of the inner shell layer of Geukensia demissa (Dillwyn) varies with both the season of calcium carbonate deposition (or dissolution) and the latitude of sampled populations. Living specimens (n = 510) were sampled at monthly and, occasionally, biweekly intervals over a 3-year period from a natural intertidal population in Gulf of Maine estuarine waters. Scanning electron microscopic examination of the inner shell layer growth surface and fractured shell sections of the sampled specimens suggests that the observed structural changes reflect seasonal cycles of aragonite deposition and dissolution. Discrete nacreous tablets generally are deposited during the warmer months of the year from May through September. During the remaining months of the year, varying degrees of shell dissolution are apparent from ultrastructural examination of the inner shell layer growth surface and fractured shell sections. Additional specimens (n = 285) were sampled during various seasons from six geographically separated populations from Prince Edward Island, Canada to Cape Kennedy, Florida, USA. Examination of acetate peel replicas and polished thin sections of shells from northern populations has revealed the presence of three distinct types of aragonitic microstructure (granular, simple prismatic, and nacre), with an increased percentage of granular structure relative to that present in shells from more southern populations. Granular microstructure is absent in shells from North Carolina and Florida populations; in the inner shell layer of specimens from these southern localities, extensive regions of nacre alternate with horizons of simple prismatic aragonite. It is suggested that area percentages of the various microstructures (particularly granular), when viewed in consistently-oriented antero-posterior shell sections, may be highly correlated with mean annual seawater temperatures. Ecological and paleoecological applications of the observed microstructural changes in the inner shell layer of this species include temporal and spatial temperature gradient reconstructions, as well as analytical studies of demographic (and individual organism) growth rates and age structure

He 2-104: A link between symbiotic stars and planetary nebulae

Ultraviolet, optical and infrared observations of He 2-104 are presented, and estimates for some of the physical properties of the nebular shell are made. It is argued that He 2-104 is in transition between the D-type symbiotic star and bipolar planetary nebula phases and, as such, represents a link between subclasses of these two types of objects. The model includes a binary system with a Mira variable and a hot, evolved star. Previous mass loss has resulted in the formation of a disk of gas and dust around the whole system, while the hot star has an accretion disk which produces the observed highly ionized emission line spectrum. Emission lines from cooler, lower density gas is also observed to come from the nebula. In addition, matter is flowing out of the system in a direction perpendicular to the disk with a high velocity and is impacting upon the previously-ejected red giant wind and/or the ambient interstellar medium

Mental Training as a Tool in the Neuroscientific Study of Brain and Cognitive Plasticity

Although the adult brain was once seen as a rather static organ, it is now clear that the organization of brain circuitry is constantly changing as a function of experience or learning. Yet, research also shows that learning is often specific to the trained stimuli and task, and does not improve performance on novel tasks, even very similar ones. This perspective examines the idea that systematic mental training, as cultivated by meditation, can induce learning that is not stimulus or task specific, but process specific. Many meditation practices are explicitly designed to enhance specific, well-defined core cognitive processes. We will argue that this focus on enhancing core cognitive processes, as well as several general characteristics of meditation regimens, may specifically foster process-specific learning. To this end, we first define meditation and discuss key findings from recent neuroimaging studies of meditation. We then identify several characteristics of specific meditation training regimes that may determine process-specific learning. These characteristics include ongoing variability in stimulus input, the meta-cognitive nature of the processes trained, task difficulty, the focus on maintaining an optimal level of arousal, and the duration of training. Lastly, we discuss the methodological challenges that researchers face when attempting to control or characterize the multiple factors that may underlie meditation training effects

Small-Scale Forestry and Carbon Offset Markets: an Empirical Study of Vermont Current Use Forest Landowner Willingness to Accept Carbon Credit Programs

This study investigates the preferences of small forest landowners regarding forest carbon credit programs while documenting characteristics of potentially successful frameworks. We designed hypothetical carbon credit programs with aggregated carbon offset projects and requirements of existing voluntary and compliance protocols in mind. We administered a mail survey to 992 forest landowners in Vermont’s Current Use Program utilizing best-worst choice, a novel preference elicitation technique, to elicit their preferences about these programs. We found that small forest landowners see revenue as the most important factor in a carbon credit program and the duration of the program as the least important factor. Landowners reported that shorter program duration, higher revenue, and lower withdrawal penalties positively impact their willingness to accept forest carbon credit programs. Notably, our study includes carbon credit program implementer as a key program attribute, allowing us to quantify landowners’ tradeoffs between non-profit, for-profit, and government organizations. Overall, we found that landowners significantly prefer working with a non-profit organization. Based on monetary estimates of willingness-to-accept compensation, our results suggest that aggregated forest carbon offset projects incorporating small forest landowners could be piloted successfully in Vermont by non-profit organizations while maintaining relatively strict guidelines of existing carbon offset protocols

Calcium carbonate dissolution rates in hydrothermal vent fields of the Guaymas Basin

Analysis of bivalve shell fragments that were embedded in epoxy blocks, mounted on titanium stakes, and deployed by DSRV Alvin at 5 sites in the Southern Trough of the Guaymas Basin (27°00′N, 111°24.55′W; depth 2012 m) indicates significant variation of calcium carbonate dissolution in in situ exposures of more than 900 days. Arrays of shell fragments of six bivalve species (i.e., Bathymodiolus thermophilus, Calyptogena magnifica, Calyptogena sp., Corbicula fluminea, Crassostrea virginica and Mytilus edulis) were positioned −17 cm, −7 cm and −2.5 cm below the sediment-water interface and 2.5 cm, 7 cm and 17 cm above the sediment-water interface in hydrothermal vent fields of the basin. Maximum dissolution rates for both calcite (mean = 86 μm/yr) and aragonite (mean = 312 μm/yr) were found in epoxy blocks located at the deepest point sampled in the sediment column (depth = 17 cm). Minimum dissolution rates of calcite and aragonite were found 7 cm (mean = 26 μm/yr) and 2.5 cm (mean = 96 μm/yr) above the sediment-water interface, respectively. Intermediate rates of dissolution were recorded 17 cm above the sediment-water interface (mean = 40 μm/yr for calcite and 126 μm/yr for aragonite). Mean rates of aragonite dissolution ranged from 59 μm/yr (site 5; clam area) to 227 μm/yr (site 3; clam area), and those of calcite dissolution ranged from 13 μm/yr (site 3; clam area) to 94 μm/yr (site 4; bacterial mat area). Dissolution rates were consistently highest in the bacterial mat area (site 4; mean = 94 μm/yr for calcite and 223 μm/yr for aragonite). Rates of calcium carbonate dissolution reported here for hydrothermal vent fields of the Guaymas Basin compare favorably with those of Rose Garden (Galapagos Rift) and 21N (East Pacific Rise) hydrothermal vent sites. These results have important implications for assessing biological rate processes in deep-sea hydrothermal vent environments

Growth and predation activity at deep-sea hydrothermal vents along the Galápagos Rift

Growth rates of unclassified mussels collected from hydrothermal vents on the Pacific Ocean (2500 m) are among the highest recorded for deep-sea species. Mature mussels have mean growth rates of about 1 cm yr-1 which are comparable to growth rates of shallow water mussels...

Practical Spectrophotometric Assay for the \u3cem\u3edapE\u3c/em\u3e-Encoded \u3cem\u3eN\u3c/em\u3e-Succinyl-L,L-Diaminopimelic Acid Desuccinylase, a Potential Antibiotic Target

A new enzymatic assay for the bacterial enzyme succinyl-diaminopimelate desuccinylase (DapE, E.C. 3.5.1.18) is described. This assay employs N6-methyl-N2-succinyl-L,L-diaminopimelic acid (N6-methyl-L,L-SDAP) as the substrate with ninhydrin used to detect cleavage of the amide bond of the modified substrate, wherein N6-methylation enables selective detection of the primary amine enzymatic product. Molecular modeling supported preparation of the mono-N6-methylated-L,L-SDAP as an alternate substrate for the assay, given binding in the active site of DapE predicted to be comparable to the endogenous substrate. The alternate substrate for the assay, N6-methyl-L,L-SDAP, was synthesized from the tert-butyl ester of Boc-L-glutamic acid employing a Horner-Wadsworth-Emmons olefination followed by an enantioselective reduction employing Rh(I)(COD)(S,S)-Et-DuPHOS as the chiral catalyst. Validation of the new ninhydrin assay was demonstrated with known inhibitors of DapE from Haemophilus influenza (HiDapE) including captopril (IC50 = 3.4 [± 0.2] μM, 3-mercaptobenzoic acid (IC50 = 21.8 [±2.2] μM, phenylboronic acid (IC50 = 316 [± 23.6] μM, and 2-thiopheneboronic acid (IC50 = 111 [± 16] μM. Based on these data, this assay is simple and robust, and should be amenable to high-throughput screening, which is an important step forward as it opens the door to medicinal chemistry efforts toward the discovery of DapE inhibitors that can function as a new class of antibiotics

CO and C_2 Absorption Toward W40 IRS 1a

The H II region W40 harbors a small group of young, hot stars behind roughly 9 magnitudes of visual extinction. We have detected gaseous carbon monoxide (CO) and diatomic carbon (C_2) in absorption toward the star W40 IRS 1a. The 2-0 R0, R1, and R2 lines of 12CO at 2.3 micron were measured using the CSHELL on the NASA IR Telescope Facility (with upper limits placed on R3, R4, and R5) yielding an N_CO of (1.1 +/- 0.2) x 10^18 cm^-2. Excitation analysis indicates T_kin > 7 K. The Phillips system of C_2 transitions near 8775 Ang. was measured using the Kitt Peak 4-m telescope and echelle spectrometer. Radiative pumping models indicate a total C_2 column density of (7.0 +/- 0.4) x 10^14 cm^-2, two excitation temperatures (39 and 126 K), and a total gas density of n ~ 250 cm^-3. The CO ice band at 4.7 micron was not detected, placing an upper limit on the CO depletion of delta < 1 %. We postulate that the sightline has multiple translucent components and is associated with the W40 molecular cloud. Our data for W40 IRS 1a, coupled with other sightlines, shows that the ratio of CO/C_2 increases from diffuse through translucent environs. Finally, we show that the hydrogen to dust ratio seems to remain constant from diffuse to dense environments, while the CO to dust ratio apparently does not.Comment: To appear in The Astrophysical Journal 17 pages total, 5 figures Also available at http://casa.colorado.edu/~shuping/research/w40/w40.htm

MusE GAs FLOw and Wind (MEGAFLOW) I: First MUSE results on background quasars

The physical properties of galactic winds are one of the keys to understand galaxy formation and evolution. These properties can be constrained thanks to background quasar lines of sight (LOS) passing near star-forming galaxies (SFGs). We present the first results of the MusE GAs FLOw and Wind (MEGAFLOW) survey obtained of 2 quasar fields which have 8 MgII absorbers of which 3 have rest-equivalent width greater than 0.8 \AA. With the new Multi Unit Spectroscopic Explorer (MUSE) spectrograph on the Very Large Telescope (VLT), we detect 6 (75$\%$) MgII host galaxy candidates withing a radius of 30 arcsec from the quasar LOS. Out of these 6 galaxy--quasar pairs, from geometrical arguments, one is likely probing galactic outflows, two are classified as "ambiguous", two are likely probing extended gaseous disks and one pair seems to be a merger. We focus on the wind$-$pair and constrain the outflow using a high resolution quasar spectra from Ultraviolet and Visual Echelle Spectrograph (UVES). Assuming the metal absorption to be due to gas flowing out of the detected galaxy through a cone along the minor axis, we find outflow velocities of the order of $\approx$ 150 km/s (i.e. smaller than the escape velocity) with a loading factor, $\eta =\dot M_{\rm out}/$SFR, of $\approx$ 0.7. We see evidence for an open conical flow, with a low-density inner core. In the future, MUSE will provide us with about 80 multiple galaxy$-$quasar pairs in two dozen fields.Comment: 20 pages, 16 figures, accepted for publication in Ap