Douglas-fir seedling quality in biochar-amended peat substrates

Artificial forest regeneration using nursery produced growing stock is commonplace in the Pacific Northwest. High quality seedlings are needed for outplanting success, which depends on a seedling’s ability to establish new roots and overcome stress. Containerized seedling stock is typically grown in artificial growing media.  Peat, a popular component of growing media, is a non-renewable resource.  Biochar has similar physical attributes to peat, which makes it a potential alternative.  In our study, we grew Douglas-fir seedlings in containers with biochar-amended peat-based growing media to determine if biochar could improve seedling quality. Douglas-fir seeds were sown in March 2016 and seedlings were grown under standard light and temperature conditions at an operational forest nursery for nine months. After nine months, seedling quality was assessed for height, diameter, cold hardiness, and root growth potential. Using biochar did not improve Douglas-fir seedling quality, except for slightly increasing cold hardiness and root growth potential for equivalently sized seedlings. Seedlings grown without biochar had increased height and diameter compared to seedlings with biochar and they had higher root growth potential (all dependent on fertilizer rates). Douglas-fir seedling quality might be improved with biochar amendment if negative growth impacts of soil reaction can be overcome

Towards a High Energy Theory for the Higgs Phase of Gravity

Spontaneous Lorentz violation due to a time-dependent expectation value for a massless scalar has been suggested as a method for dynamically generating dark energy. A natural candidate for the scalar is a Goldstone boson arising from the spontaneous breaking of a U(1) symmetry. We investigate the low-energy effective action for such a Goldstone boson in a general class of models involving only scalars, proving that if the scalars have standard kinetic terms then at the {\em classical} level the effective action does not have the required features for spontaneous Lorentz violation to occur asymptotically $(t \to \infty)$ in an expanding FRW universe. Then we study the large $N$ limit of a renormalizable field theory with a complex scalar coupled to massive fermions. In this model an effective action for the Goldstone boson with the properties required for spontaneous Lorentz violation can be generated. Although the model has shortcomings, we feel it represents progress towards finding a high energy completion for the Higgs phase of gravity.Comment: 20 pages, 5 figures;fixed typos and added reference

Woody energy crops in the southeastern United States: two centuries of practitioner experience,”

Hardwood plantations Productivity Southern pine plantations Commercial production costs Bioenergy feedstocks a b s t r a c t Forest industry experts were consulted on the potential for hardwood tree species to serve as feedstock for bioenergy in the southeastern United States. Hardwoods are of interest for bioenergy because of desirable physical qualities, genetic research advances, and growth potential. Yet little data is available regarding potential productivity and costs. This paper describes required operations and provides a realistic estimate of the costs of producing bioenergy feedstock based on commercial experiences. Forestry practitioners reported that high productivity rates in southeastern hardwood plantations are confined to narrow site conditions or require costly inputs. Eastern cottonwood and American sycamore grow quickly on rich bottomlands, but are also prone to pests and disease. Sweetgum is frost hardy, has few pest or disease problems, and grows across a broad range of sites, yet growth rates are relatively low. Eucalypts require fewer inputs than do other species and offer high potential productivity but are limited by frost to the lower Coastal Plain and Florida. Further research is required to study naturally regenerated hardwood biomass resources. Loblolly pine has robust site requirements, growth rates rivaling hardwoods, and lower costs of production. More time and investment in silviculture, selection, and breeding will be needed to develop hardwoods as competitive biofuel feedstock species. Because of existing stands and fully developed operations, the forestry community considers loblolly pine to be a prime candidate for plantation bioenergy in the Southeast. ª 2010 Elsevier Ltd. All rights reserved. Background i o m a s s a n d b i o e n e r g y 3 4 ( 2 0 1 0 ) 1 6 5 5 e1 6 6 6 0961-9534/$ e see front matter

Forest production responses to irrigation and fertilization are not explained by shifts in allocation.

Production increases in intensively managed forests have been obtained by improving resource availability through water and nutrient amendments. Increased stem production has been attributed to shifts in growth from roots to shoot, and such shifts would have important implications for below ground carbon sequestration. We examined above and below ground growth and biomass accumulation and distribution in two eastern cottonwood clones and American sycamore receiving irrigation(I), fertilization(F), orirrigation+fertilization(IF) and compared with non-treated controls(C). Above ground growth and biomass accumulation responded positively to both I and F in all genotypes. After three growing seasons, the largest trees were sycamore receiving the IF treatment, with a total mean annual biomass production of 9.4 Mg ha -1 yr -1. Total cottonwood mean annual biomass production in both clones was >5.0 Mg ha -1 yr -1 in the IF treatment. Above ground biomass production was 6.3 and >3.1 Mg ha -1 yr -1 for sycamore and cottonwoods, respectively. Total root mass fraction was lower in high resource treatments and declined as stands aged. To compare allocation in trees of equal size, we used allometric relationships between above and below ground tissue. Allometric relationships between woody perennial tissues rarely differed among treatments. Improved resource availability caused large increases in growth and consequently accelerated development, but it had little effect on below ground allocation that was not explained by development. Reports of shifting below ground allocation due to soil resource availability must account for developmental effects if they are to accurately evaluate direct impacts of soil resources

Bayesian High-Redshift Quasar Classification from Optical and Mid-IR Photometry

We identify 885,503 type 1 quasar candidates to i<22 using the combination of optical and mid-IR photometry. Optical photometry is taken from the Sloan Digital Sky Survey-III: Baryon Oscillation Spectroscopic Survey (SDSS-III/BOSS), while mid-IR photometry comes from a combination of data from the Wide-Field Infrared Survey Explorer (WISE) "ALLWISE" data release and several large-area Spitzer Space Telescope fields. Selection is based on a Bayesian kernel density algorithm with a training sample of 157,701 spectroscopically-confirmed type-1 quasars with both optical and mid-IR data. Of the quasar candidates, 733,713 lack spectroscopic confirmation (and 305,623 are objects that we have not previously classified as photometric quasar candidates). These candidates include 7874 objects targeted as high probability potential quasars with 3.5<z<5 (of which 6779 are new photometric candidates). Our algorithm is more complete to z>3.5 than the traditional mid-IR selection "wedges" and to 2.2<z<3.5 quasars than the SDSS-III/BOSS project. Number counts and luminosity function analysis suggests that the resulting catalog is relatively complete to known quasars and is identifying new high-z quasars at z>3. This catalog paves the way for luminosity-dependent clustering investigations of large numbers of faint, high-redshift quasars and for further machine learning quasar selection using Spitzer and WISE data combined with other large-area optical imaging surveys.Comment: 54 pages, 17 figures; accepted by ApJS Data for tables 1 and 2 available at http://www.physics.drexel.edu/~gtr/outgoing/optirqsos/data/master_quasar_catalogs.011414.fits.bz2 and http://www.physics.drexel.edu/~gtr/outgoing/optirqsos/data/optical_ir_quasar_candidates.052015.fits.bz

S-Wave Scattering of Charged Fermions by a Magnetic Black Hole

We argue that, classically, $s$-wave electrons incident on a magnetically charged black hole are swallowed with probability one: the reflection coefficient vanishes. However, quantum effects can lead to both electromagnetic and gravitational backscattering. We show that, for the case of extremal, magnetically charged, dilatonic black holes and a single flavor of low-energy charged particles, this backscattering is described by a perturbatively computable and unitary $S$-matrix, and that the Hawking radiation in these modes is suppressed near extremality. The interesting and much more difficult case of several flavors is also discussed.Comment: 9p

The Development of Day-night Differences in Sleep and Wakefulness in Norway Rats and the Effect of Bilateral Enucleation

The suprachiasmatic nucleus (SCN) exhibits circadian rhythmicity in fetal and infant rats, but little is known about the consequences of this rhythmicity for infant behavior. Here, in Experiment 1, we measured sleep and wakefulness in rats during the day and night in postnatal day (P)2, P8, P15 and P21 subjects. As early as P2, day-night differences in sleep-wake activity were detected. Nocturnal wakefulness began to emerge around P15 and was reliably expressed by P21. We hypothesized that the process of photic entrainment over the first postnatal week, which depends upon the development of connectivity between the retinohypothalamic tract (RHT) and the SCN, influences the later emergence of nocturnal wakefulness. To test this hypothesis, in Experiment 2 infant rats were enucleated bilaterally at P3 and P11, that is, before and after photic entrainment. Whereas pups enucleated at P11 and tested at P21 exhibited increased wakefulness at night, identical to sham controls, pups enucleated at P3 and tested at P21 exhibited the opposite pattern of increased wakefulness during the day. Pups tested at P28 and P35 exhibited this same pattern of increased daytime wakefulness. All together, these results suggest that prenatal and postnatal experience modulates the development of species-typical circadian sleep-wake patterns. Moreover, we suggest that visual system stimulation, via the RHT’s connections with the SCN, exerts an organizational influence on the developing circadian system and, consequently, contributes to the emergence of nocturnality in this species

Black Holes with a Generalized Gravitational Action

Microscopic black holes are sensitive to higher dimension operators in the gravitational action. We compute the influence of these operators on the Schwarzschild solution using perturbation theory. All (time reversal invariant) operators of dimension six are included (dimension four operators don't alter the Schwarzschild solution). Corrections to the relation between the Hawking temperature and the black hole mass are found. The entropy is calculated using the Gibbons-Hawking prescription for the Euclidean path integral and using naive thermodynamic reasoning. These two methods agree, however, the entropy is not equal to 1/4 the area of the horizon.Comment: plain tex(uses phyzzx.tex), 8 pages, CALT-68-185

A Quantum Mechanical Model of Spherical Supermembranes

We present a quantum mechanical model of spherical supermembranes. Using superfields to represent the cartesian coordinates of the membrane, we are able to exactly determine its supersymmetric vacua. We find there are two classical vacua, one corresponding to an extended membrane and one corresponding to a point-like membrane. For the ${\mathcal N} = 2$ case, instanton effects then lift these vacua to massive states. For the ${\mathcal N} = 4$ case, there is no instanton tunneling, and the vacua remain massless. Similarities to spherical supermembranes as giant gravitons and in Matrix theory on pp-waves is discussed.Comment: 9 page

Ice damage in loblolly pine: Understanding the factors that influence susceptibility.

Abstract: Winter ice storms frequently occur in the southeastern United States and can severely damage softwood plantations. In January 2004, a severe storm deposited approximately 2 cm of ice on an intensively managed 4-year-old loblolly pine (Pinus taeda L.) plantation in South Carolina. Existing irrigation and fertilization treatments presented an opportunity to examine the effects of resource amendments on initial ice damage and subsequent recovery. Fertilized treatments showed more individual stem breakage, whereas non fertilized treatments showed more stem bending; however, the proportion of undamaged trees did not differ between treatments. Irrigation did not influence the type of damage. Trees that experienced breakage during the storm were taller with larger diameter and taper and leaf, branch, and crown biomass compared with unbroken trees. One growing season after ice damage, relative height increases were significantly greater for trees experiencing stem breakage compared with unbroken trees; however, relative diameter increases were significantly lower for these trees. Relative diameter increases for broken trees were smaller for fertilized treatments compared with nonfertilized treatments. A reduction in wood strength was ruled out as the cause of greater breakage in fertilized trees; rather, fertilized trees had reached an intermediate diameter range known to be susceptible to breakage under ice loading