Abstract
In shrub willow biomass crop (
SWBC
) production systems, the soil
CO
2
efflux (F
c
) component in the carbon cycle remains poorly understood. This study assesses (i) differences of F
c
...rates among the 5‐, 12‐, 14‐, and 19‐year‐old
SWBC
s with two treatments: continuous production (regrowth) willow fields that were harvested and allowed to regrow, and willow fields that were harvested, killed, and then stools and roots were ground into the soil (removal); (ii) temporal and spatial variations of F
c
rates; (iii) root respiration contributions to total F
c
; and (iv) climatic variables affecting F
c
. During the growing season (May to September), F
c
rates showed no statistically significant differences across different ages (
P
= 0.664), and between treatments (
P
= 0.351); however, there was an interaction between age and treatment (
P
= 0.001). Similarly, during the dormant season (October to April), F
c
rates revealed no statistically significant differences across different ages (
P
= 0.305) and treatment interaction with age (
P
= 0.097). F
c
rates differed significantly (
P
< 0.001) among different times of the day and times of the year. F
c
rates, between 00 and 1059 h, between 1100 and 1659 h, and between 1700 and 2400 h displayed consistency from May to November; however, F
c
rates in these three time intervals showed significant differences (
P
< 0.0001). In December, F
c
rates remained constant over 24 h. F
c
rates demonstrated higher temporal and spatial variations among willow age classes than between regrowth and removal treatments. Temporal and spatial variations of F
c
were higher during the dormant season than during the growing season. The proportion of root respiration to total F
c
ranged from 18 to 33% across age classes. F
c
rates showed strong association with soil and air temperatures, and relative humidity.
We described a general pattern of cohort development following two types of even-aged reproduction methods in northern hardwoods. Three clearcut sites initially had divergent numbers of stems, ...because of variable amounts of advance regeneration. By 10 years, total stem densities became quite similar across sites. Three sites treated by shelterwood seed cutting lacked advance regeneration. Compared with the clearcuts, seedlings became established at much higher stem densities there, and even early cohort development followed a consistent pattern. By 20-25 years, both the clearcut and shelterwood sites supported 7600-8900 total stems/ha. Stems > or = 2.54 cm diameter at breast height peaked at about 6000, but by age 15 following clear-cutting, and not until age 20 after shelterwood seed cutting. The time lag likely reflects initial differences in advance regeneration, and possibly other factors between sites. Basal area at the clearcut sites reached 26 m2/ha within about 25 years. At the shelterwood sites it reached 22 m2/ha by age 25. The quadratic stand diameter increased consistently across sites and treatments. Regression models describe changes in numbers of total stems, numbers of saplings, stand basal area, and quadratic stand diameter for each treatment.
Abstract
Forty-two forestry best management practices (BMPs) were assessed to determine the extent of voluntary application and their effectiveness in preventing water quality impacts in New York ...State. These BMPs were evaluated on 61 timber-harvested sites in the Catskill region (CR), and 53 timber harvested sites in the Adirondack region (AR) during the summers of 1997 and 1998. The overall application of suggested BMPs was 78% for haul roads, 87% for landings, 59% for skid trails, 88% for equipment maintenance/operation, and 73% for buffer strips. Departures were common for BMPs concerned with draining water off haul roads and skid trails, and for stream crossings; more attention must be devoted to those practices. Effectiveness of BMPs was apparent when they were applied. Nonparametric statistical tests showed a strong relationship between BMP application and prevention of sediment movement. Limiting sediment movement protects surface water. In the CR, 27 of the 33 BMPs tested showed a statistically significant (P < 0.10) relationship between BMP application and sediment movement. Similar results were observed in the AR; 26 of the BMPs tested were significantly associated with sediment movement. Imperfect application of BMPs reduced effectiveness. Road drainage structures, for example, generally failed to adequately control erosion when spacing between drainage structures was excessive. North. J. Appl. For. 17(4): 125–134.
Three-dimensional imaging can improve the understanding and comprehension of complex anatomy. Recent advances in software development allow the construction of a virtual endoscopic view of anatomic ...structures. This report applies virtual endoscopic capabilities to imaging of the internal auditory canal.
We conducted a retrospective case review at a tertiary referral center of patients with abnormal internal auditory canal anatomy on computed tomography.
Computed tomography images were obtained using conventional clinical algorithms involving multiple, 1-mm-thick slices through the temporal bone. Three-dimensional reconstructions were made using General Electric Advantage Windows Navigator software. The virtual endoscopic image-processing algorithm used selected image intensity threshold levels to visualize internal auditory canal anatomy from an endoscopic perspective.
Eleven cases of abnormalities of the internal auditory canal were retrospectively identified. Clinical applications using the virtual endoscopic images are presented. The virtual endoscopic images supported prior clinical decision making in 6 of the 11 cases evaluated.
This technique shows promise for the diagnosis, surgical planning, and teaching of temporal bone anatomy. Usefulness is dependent on acquisition parameters and clinical indications for examination.
Precommercial thinning (PCT), a silvicultural treatment commonly used to increase individual tree growth rate and reduce the time required to attain merchantability for young fir (Abies spp.)-spruce ...(Picea spp.) stands, is both biologically effective and expensive ($300-500/ha in 1993). Forest managers desire to allocate silvicultural capital to maximize return on investment. This study was initiated to identify criteria that could be utilized to rank sites according to response of balsam fir Abies balsamea (L.) Mill. to PCT. Sixty-two plots were established in young fir-spruce stands in Maine that had been precommercially thinned between 1977 and 1987. Volume increments 3 yr prior to (VI3PRE) and 3 yr after (VI3POST) PCT were reconstructed from detailed stem analyses of 427 balsam fir trees. Increased radial increment following PCT was visually apparent and significant for each sample tree. The magnitude of the response was strongly affected by soil drainage class. Regression with dummy variables showed that VI3POST, expressed as a function of VI3PRE, increased as soil drainage class improved from poorly (mottling within 10 cm of mineral soil surface) to well (mottling 60 cm below mineral soil surface) and somewhat-excessively drained (loam textured cap overlying deep sand), then decreased for trees growing on excessively drained (sandy-textured) soils. Soil drainage class can be used effectively to rank sites according to expected response to PCT on large land bases
Abstract
European larch is a fast-growing exotic species that shows promise in alleviating projected fiber supply shortages with numerous plantations being established in the Lake States, the ...Northeast, and Canada during the last two decades. Prescribing thinning regimes for these plantations would be facilitated through the use of a stocking chart. Few older plantations exist in North America, however, thus fitting equations to construct an A-line that requires data from a large number of stands is not possible. We introduce a new approach to constructing an A-line by using the stand density index that in essence is a modification of the traditional tree area ratio approach. We then invoke the self-thinning rule to produce a reference line for Maximum Average Density and an equation for open-grown trees to produce a reference line for Full Site Occupancy in the construction a stocking chart for field use. We also provide yield estimates by diameter class at maximum and minimum stocking levels. North. J. Appl. For. 20(1):34–38.
•Comparison of fossil eumelanin reveals constraints on preservation.•Alteration of eumelanin is primarily due to maturation.•Alteration of eumelanin is largely independent of age and diagenetic ...mineralization.•Alteration of eumelanin is not accompanied by a change in granule morphology.
Melanins are polymeric phenolic pigments classified into two groups based on their chemical structures and molecular precursors: eumelanin (brown–black) and pheomelanin (yellow–red). Eumelanin is highly resilient and has a proven fossil record, extending back at least ∼200Ma. It is widespread in the biological world, occurring in fungi, the ink sacs of cephalopods, the feathers of birds, and the hair, skin, eyes, brain and inner ears of mammals. Although the presence and chemical attributes of fossil eumelanin have been documented, there are few data constraining its long term survival. Here we use a diversity of analytical techniques to compare the chemistry and morphology of fossilized cephalopod ink from three deposits of similar age and lithology, but different maturation histories. We demonstrate that the chemistry of eumelanin begins to alter at the onset of the oil window and is largely independent of age. The decrease in surviving melanin is accompanied by an increase in the relative abundance of organic macromolecular material (kerogen) but, critically for the correct interpretation of fossils, is not accompanied by a consistent change in granule morphology.
An unusual catch in the nasopharynx Briggs, Russell D.; Pou, Anna M.; Friedman, Norman R.
American journal of otolaryngology,
09/2001, Letnik:
22, Številka:
5
Journal Article
The worldwide burden of kidney disease is rising, but public awareness remains limited, underscoring the need for more effective communication by stakeholders in the kidney health community. Despite ...this need for clarity, the nomenclature for describing kidney function and disease lacks uniformity. In June 2019, Kidney Disease: Improving Global Outcomes (KDIGO) convened a Consensus Conference with the goal of standardizing and refining the nomenclature used in the English language to describe kidney function and disease, and of developing a glossary that could be used in scientific publications. Guiding principles of the conference were that the revised nomenclature should be patient-centered, precise, and consistent with nomenclature used in the KDIGO guidelines. Conference attendees reached general consensus on the following recommendations: (i) to use “kidney“ rather than “renal” or “nephro-” when referring to kidney disease and kidney function; (ii) to use “kidney failure” with appropriate descriptions of presence or absence of symptoms, signs, and treatment, rather than “end-stage kidney disease”; (iii) to use the KDIGO definition and classification of acute kidney diseases and disorders (AKD) and acute kidney injury (AKI), rather than alternative descriptions, to define and classify severity of AKD and AKI; (iv) to use the KDIGO definition and classification of chronic kidney disease (CKD) rather than alternative descriptions to define and classify severity of CKD; and (v) to use specific kidney measures, such as albuminuria or decreased glomerular filtration rate (GFR), rather than “abnormal” or “reduced” kidney function to describe alterations in kidney structure and function. A proposed 5-part glossary contains specific items for which there was general agreement. Conference attendees acknowledged limitations of the recommendations and glossary, but they considered standardization of scientific nomenclature to be essential for improving communication.
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