92 research outputs found
Recommended from our members
Identification of variables influencing residual stand damage from skyline thinning of young western hemlock-Sitka spruce stand
Western hemlock and Sitka spruce are relatively thin-
barked species and susceptible to damage during thinning
operations. Damage to the wood allows decay-causing fungi
to enter resulting in loss of merchantable volume at the
time of final harvest. Cable yarding systems are needed for
much of the thinning because most hemlock-spruce stands in
the Pacific Northwest are located on steep slopes and
fragile soils. It is during these thinning operations that
much of the damage occurs. The purpose of this study was to
determine the significant harvesting variables affecting
residual stand damage due to cable thinning a 30-year-old
hemlock -spruce stand.
Detailed stand damage measurements were made during
logging on nine skyline units in two study areas in western
Oregon. Less detailed damage was measured on 18 other units
to determine differences in damage levels between three
different thinning treatments: conventional low intensity
thinning, conventional high intensity thinning, and a
herringlone (strip) thinning. Twenty-two variables were
measured in two categories: harvesting variables and stand
damage variables. Total scar area per turn (ft2/turn) was
used as the dependent variable.
As a result of regression analysis, the following
variables were found to most significantly influence
residual stand damage: number of carriage repositions, log.
angle, carriage clearance., narrow treatment, rigging
slinger, and cutter. An analysis of variance showed mean
scar area per acre for the narrow and wide treatments were
significantly different from the strip treatment.
Only 12 percent of the residual stand (trees/acre) in
the strip treatment were damaged. The narrow and wide
treatments experienced much higher levels of 47 and 61
percent, respectively. Conventional thinning treatments
experienced extensive damage levels (84.78 ft2/acre in the
narrow treatment and 91.64 ft2/acre in the wide treatment)
compared to the strip treatment (17.57 ft2/acre).
Individual scars ranged in size from 0.02 to 14.00 square
feet. Of the total scar area in the detailed units, 66.6
oercent was found within 20 feet of the skyline corridor
centerline
Dabrafenib, alone or in combination with trametinib, in BRAF V600–mutated pediatric Langerhans cell histiocytosis
Langerhans cell histiocytosis (LCH) is a rare, heterogenous, neoplastic disorder primarily affecting children. BRAF mutations have been reported in >50% of patients with LCH. The selective BRAF inhibitor, dabrafenib, in combination with the MEK1/2 inhibitor, trametinib, has been approved in select BRAF V600–mutant solid tumors. Two open-label phase 1/2 studies were conducted in pediatric patients with BRAF V600–mutant, recurrent/refractory malignancies treated with dabrafenib monotherapy (CDRB436A2102; NCT01677741) or dabrafenib plus trametinib (CTMT212X2101; NCT02124772). The primary objectives of both studies were to determine safe and tolerable doses that achieve similar exposure to the approved doses for adults. Secondary objectives included safety, tolerability, and preliminary antitumor activity. Thirteen and 12 patients with BRAF V600–mutant LCH received dabrafenib monotherapy and in combination with trametinib, respectively. Investigator-assessed objective response rates per Histiocyte Society criteria were 76.9% (95% confidence interval [CI], 46.2-95.0) and 58.3% (95% CI, 27.7-84.8) in the monotherapy and combination studies, respectively. More than 90% of responses were ongoing at study completion. The most common treatment-related adverse events (AEs) were vomiting and increased blood creatinine with monotherapy and pyrexia, diarrhea, dry skin, decreased neutrophil count, and vomiting with combination therapy. Two patients each discontinued treatment with monotherapy and combination therapy because of AEs. Overall, dabrafenib monotherapy or in combination with trametinib demonstrated clinical efficacy and manageable toxicity in relapsed/refractory BRAF V600–mutant pediatric LCH, with most responses ongoing. Safety was consistent with that reported in other pediatric and adult conditions treated with dabrafenib plus trametinib
Robotic Finger Assembly
A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange
Robotic Finger Assembly
A robotic hand includes a finger with first, second, and third phalanges. A first joint rotatably connects the first phalange to a base structure. A second joint rotatably connects the first phalange to the second phalange. A third joint rotatably connects the third phalange to the second phalange. The second joint and the third joint are kinematically linked such that the position of the third phalange with respect to the second phalange is determined by the position of the second phalange with respect to the first phalange
Gene Electro Transfer of Plasmid Encoding Vascular Endothelial Growth Factor for Enhanced Expression and Perfusion in the Ischemic Swine Heart
Myocardial ischemia can damage heart muscle and reduce the heart\u27s pumping efficiency. This study used an ischemic swine heart model to investigate the potential for gene electro transfer of a plasmid encoding vascular endothelial growth factor for improving perfusion and, thus, for reducing cardiomyopathy following acute coronary syndrome. Plasmid expression was significantly greater in gene electro transfer treated tissue compared to injection of plasmid encoding vascular endothelial growth factor alone. Higher gene expression was also seen in ischemic versus non-ischemic groups with parameters 20 Volts (
Tendon Driven Finger Actuation System
A humanoid robot includes a robotic hand having at least one finger. An actuation system for the robotic finger includes an actuator assembly which is supported by the robot and is spaced apart from the finger. A tendon extends from the actuator assembly to the at least one finger and ends in a tendon terminator. The actuator assembly is operable to actuate the tendon to move the tendon terminator and, thus, the finger
Recommended from our members
Skyline thinning a western hemlock-Sitka spruce stand : harvesting costs and stand damage
Bioelectric Effects of Intense Nanosecond Pulses
Electrical models for biological cells predict that reducing the duration of applied electrical pulses to values below the charging time of the outer cell membrane (which is on the order of 100 ns for mammalian cells) causes a strong increase in the probability of electric field interactions with intracellular structures due to displacement currents. For electric field amplitudes exceeding MV/m, such pulses are also expected to allow access to the cell interior through conduction currents flowing through the permeabilized plasma membrane. In both cases, limiting the duration of the electrical pulses to nanoseconds ensures only nonthermal interactions of the electric field with subcellular structures. This intracellular access allows the manipulation of cell functions. Experimental studies, in which human cells were exposed to pulsed electric fields of up to 300 kY/cm amplitude with durations as short as 3 ns, have confirmed this hypothesis and have shown that it is possible to selectively alter the behavior and/or survival of cells. Observed nanosecond pulsed effects at moderate electric fields include intracellular release of calcium and enhanced gene expression, which could have long term implications on cell behavior and function. At increased electric fields, the application of nanosecond pulses induces a type of programmed cell death, apoptosis, in biological cells. Cell survival studies with 10 ns pulses have shown that the viability of the cells scales inversely with the electrical energy density, which is similar to the ‘dose’ effect caused by ionizing radiation. On the other hand, there is experimental evidence that, for pulses of varying durations, the onset of a range of observed biological effects is determined by the electrical charge that is transferred to the cell membrane during pulsing. This leads to an empirical similarity law for nanosecond pulse effects, with the product of electric field intensity, pulse duration, and the square root of the number of pulses as the similarity parameter. The similarity law allows one not only to predict cell viability based on pulse parameters, but has also been shown to be applicable for inducing platelet aggregation, an effect which is triggered by internal calcium release. Applications for nanosecond pulse effects cover a wide range: from a rather simple use as preventing biofouling in cooling water systems, to advanced medical applications, such as gene therapy and tumor treatment. Results of this continuing research are leading to the development of wound healing and skin cancer treatments, which are discussed in some detail
A Study of 3CR Radio Galaxies from z = 0.15 to 0.65. II. Evidence for an Evolving Radio Structure
Radio structure parameters were measured from the highest quality radio maps
available for a sample of 3CR radio galaxies in the redshift range 0.15 < z <
0.65. Combined with similar data for quasars in the same redshift range, these
morphology data are used in conjunction with a quantification of the richness
of the cluster environment around these objects (the amplitude of the
galaxy-galaxy spatial covariance function, Bgg) to search for indirect evidence
of a dense intracluster medium (ICM). This is done by searching for confinement
and distortions of the radio structure that are correlated with Bgg.
Correlations between physical size and hot spot placement with Bgg show
evidence for an ICM only at z 0.4,
suggesting an epoch of z ~ 0.4 for the formation of an ICM in these Abell
richness class 0-1, FR2-selected clusters. X-ray selected clusters at
comparable redshifts, which contain FR1 type sources exclusively, are
demonstrably richer than the FR2-selected clusters found in this study. The
majority of the radio sources with high Bgg values at z < 0.4 can be described
as ``fat doubles'' or intermediate FR2/FR1s. The lack of correlation between
Bgg and bending angle or Bgg and lobe length asymmetry suggests that these
types of radio source distortion are caused by something other than interaction
with a dense ICM. Thus, a large bending angle cannot be used as an unambiguous
indicator of a rich cluster around powerful radio sources. These results
support the hypothesis made in Paper 1 that cluster quasars fade to become
FR2s, then FR1s, on a timescale of 0.9 Gyrs (for H0 = 50 km s^-1 Mpc^-1).Comment: 44 pages, 8 figures, 2 tables; to be published in the September 2002
issue of The Astronomical Journa
Impaired word and face recognition in older adults with type 2 diabetes
Background: Older adults with type 2 diabetes mellitus (DM2) exhibit accelerated decline in some domains of cognition, including verbal episodic memory. Few studies have investigated the influence of DM2 status in older adults on recognition memory for more complex stimuli,
such as faces. Aims: In the present study, we sought to compare recognition memory performance for words, objects and faces under conditions of relatively low and high
cognitive load. Methods: Healthy older adults with good glucoregulatory control (n = 13) and older adults with DM2 (n = 24) were administered recognition memory tasks in which stimuli (faces, objects and words) were presented under conditions of either i) low (stimulus presented without a background pattern), or ii) high (stimulus presented against a background pattern) cognitive load. Results: In a subsequent recognition phase, the DM2 group recognised fewer faces than healthy controls. Further, the DM2 group exhibited word recognition deficits in the low cognitive load condition. Conclusions: The recognition memory impairment observed in the patients with DM2 has clear implications for day-to-day functioning. While these deficits were not amplified under conditions of increased cognitive load, the present study emphasises that recognition memory impairment for both words and more complex stimuli, such as faces, are a feature of DM2 in older adults
- …