8,787 research outputs found
Digital demodulation with data subcarrier tracking
Digital demodulator is based on early-late bit timing scheme coupled with Costas data tracking loop. System is successful in enhancement of weak signals from space where atmospheric and other interference media cause bit error rate to reach excessive level
Digital demodulation with data subcarrier tracking
Digital demodulation with data subcarrier trackin
An Observational Study of Tropical Cyclone Spinup in Supertyphoon Jangmi (2008) from 24 to 27 September
The article of record as published may be found at http://dx.doi.org/10.1175/MWR-D-12-00306.1An observational study of tropical cyclone intensification is performed using dropsondes, in situ flight-level
data, satellite imagery, and Electra Doppler Radar (ELDORA) during the spinup of Tropical Storm Jangmi
(2008) in the western North Pacific. This event was observed with research aircraft during the Tropical Cyclone
Structure 2008 (TCS08) field experiment over the course of 3 days as Jangmi intensified rapidly from a tropical
storm to a supertyphoon. The dropsonde analysis indicates that the peak azimuthally averaged storm-relative
tangential wind speed occurs persistently within the boundary layer throughout the spinup period and suggests
that significant supergradient winds are present near and just within the radius of maximum tangential winds. An
examination of the ELDORA data in Tropical Storm Jangmi reveals multiple rotating updrafts near the developing
eye beneath cold cloud top temperatures ≤ -65°C. In particular, there is a 12-km-wide, upright updraft
with a peak velocity of 9m s¯¹ with collocated strong low-level (z < 2 km) convergence of 2 x 10¯³ s¯¹ and
intense relative vorticity of 4 x 10¯³ s¯¹. The analysis of the corresponding infrared satellite imagery suggests
that vortical updrafts are common before and during rapid intensification. The findings of this study support
a recent paradigm of tropical cyclone intensification in which rotating convective clouds are important elements
in the spinup process. In a system-scale view of this process, the maximum tangential wind is found within the
boundary layer, where the tangential wind becomes supergradient before the air ascends into the eyewall updraft.Naval Postgraduate SchoolOffice of Naval Research (Grant N001408WR20129),National Science FoundationOffice of Naval Research (Grant N001408WR20129
Sites of monomeric actin incorporation in living PTK2 and REF-52 cells
The purpose of this study was to analyze where monomeric actin first becomes incorporated into the sarcomeric units of the stress fibers. We microinjected fluorescently labeled actin monomers into two cell lines that differ in the sarcomeric spacings of ␣-actinin and nonmuscle myosin II along their stress fibers: REF-52, a fibroblast cell line, and PtK2, an epithelial cell line. The cells were fixed at selected times after microinjection (30 s and longer) and then stained with an ␣-actinin antibody. Localization of the labeled actin and ␣-actinin antibody were recorded with low level light cameras. In both cell types, the initial sites of incorporation were in focal contacts, lamellipodia and in punctate regions of the stress fibers that corresponded to the ␣-actinin rich dense bodies. The adherent junctions between the epithelial PtK2 cells were also initial sites of incorporation. At longer times of incorporation, the actin fluorescence extended along the stress fibers and became almost uniform. We saw no difference in the pattern of incorporation in peripheral and perinuclear regions of the stress fibers. We propose that rapid incorporation of monomeric actin occurs at the cellular sites where the barbed ends of actin filaments are concentrated: at the edges of lamellipodia, the adherens junctions, the attachment plaques and in the dense bodies that mark out the sarcomeric subunits of the stress fibers. Cell Motil
Sexual Dimorphisms in Habitat-Specific Morphology and Behavior in the Green Anole Lizard
Species that occur in variable environments often exhibit morphological and behavioral traits that are specific to local habitats. Because the ability to move effectively is closely associated with structural habitat, locomotor traits may be particularly sensitive to fine-scale habitat differences. Anolis lizards provide an excellent opportunity to study the relationship between locomotion and natural perch use in the field, as laboratory studies have demonstrated that lizards that use broader perches develop longer limbs and have higher sprint speeds. We examined Anolis carolinensis (the green anole) in three habitats in close proximity. Our goals were to determine whether habitat-specific differences in hindlimb and toe morphologies occurred in a population in which perch size was variable but not manipulated, whether locomotor behaviors were associated with these morphologies, and whether habitat-specific traits differed between the sexes. We found that while juveniles in the three habitats did not differ in limb or toe morphology, adult females using broader perches had relatively longer limbs than females using narrower perches. Females also differed in toe length across habitats, but not in relation to perch diameter. Males, in contrast, exhibited differing growth patterns (allometry) in these traits, and marginal differences in locomotor behavior. Together, these results suggest that sex-specific responses in morphology and behavior, consistent with experimental observations of phenotypic plasticity, provide a mechanism for refining local habitat use
Sexual Dimorphisms in Habitat-Specific Morphology and Behavior in the Green Anole Lizard
Species that occur in variable environments often exhibit morphological and behavioral traits that are specific to local habitats. Because the ability to move effectively is closely associated with structural habitat, locomotor traits may be particularly sensitive to fine-scale habitat differences. Anolis lizards provide an excellent opportunity to study the relationship between locomotion and natural perch use in the field, as laboratory studies have demonstrated that lizards that use broader perches develop longer limbs and have higher sprint speeds. We examined Anolis carolinensis (the green anole) in three habitats in close proximity. Our goals were to determine whether habitat-specific differences in hindlimb and toe morphologies occurred in a population in which perch size was variable but not manipulated, whether locomotor behaviors were associated with these morphologies, and whether habitat-specific traits differed between the sexes. We found that while juveniles in the three habitats did not differ in limb or toe morphology, adult females using broader perches had relatively longer limbs than females using narrower perches. Females also differed in toe length across habitats, but not in relation to perch diameter. Males, in contrast, exhibited differing growth patterns (allometry) in these traits, and marginal differences in locomotor behavior. Together, these results suggest that sex-specific responses in morphology and behavior, consistent with experimental observations of phenotypic plasticity, provide a mechanism for refining local habitat use
Effects of neo-adjuvant chemotherapy for oesophago-gastric cancer on neuro-muscular gastric function
Delayed gastric emptying symptoms are often reported after chemotherapy. This study aims to characterise the effects of chemotherapy on gastric neuro-muscular function. Patients undergoing elective surgery for oesophago-gastric cancer were recruited. Acetylcholinesterase, nNOS, ghrelin receptor and motilin expressions were studied in gastric sections from patients receiving no chemotherapy (n = 3) or oesophageal (n = 2) or gastric (n = 2) chemotherapy. A scoring system quantified staining intensity (0–3; no staining to strong). Stomach sections were separately suspended in tissue baths for electrical field stimulation (EFS) and exposure to erythromycin or carbachol; three patients had no chemotherapy; four completed cisplatin-based chemotherapy within 6 weeks prior to surgery. AChE expression was markedly decreased after chemotherapy (scores 2.3 ± 0.7, 0.5 ± 0.2 and 0 ± 0 in non-chemotherapy, oesophageal- and gastric-chemotherapy groups (p < 0.03 each) respectively. Ghrelin receptor and motilin expression tended to increase (ghrelin: 0.7 ± 0.4 vs 2.0 ± 0.4 and 1.2 ± 0.2 respectively; p = 0.04 and p = 0.2; motilin: 0.7 ± 0.5 vs 2.2 ± 0.5 and 2.0 ± 0.7; p = 0.06 and p = 0.16). Maximal contraction to carbachol was 3.7 ± 0.7 g and 1.9 ± 0.8 g (longitudinal muscle) and 3.4 ± 0.4 g and 1.6 ± 0.6 (circular) in non-chemotherapy and chemotherapy tissues respectively (p < 0.05 each). There were loss of AChE and reduction in contractility to carbachol. The tendency for ghrelin receptors to increase suggests an attempt to upregulate compensating systems. Our study offers a mechanism by which chemotherapy markedly alters neuro-muscular gastric function
Adolescent Females With Communication Disorders Involved in Violence: Educators\u27 Opinions
This study focused on increasing the awareness of educational leaders about the relationship between students with communication disorders and violence. A review of selected research on adolescent females with language problems residing in a correctional facility served to support a survey study and extend discussions about the need for educational leadership within this population. Ninety-six speech-language pathologists, special educators, and teachers were surveyed about their training and knowledge on the role of communication in violence. Findings suggested the majority of participants agreed on the importance of planning prevention programs. However, they did not receive training and were uncertain about providing services to students with communication disorders. Implications are provided for administrators and other school leaders to consider when planning programs
Adolescent Females With Communication Disorders Involved in Violence: Educators\u27 Opinions
This study focused on increasing the awareness of educational leaders about the relationship between students with communication disorders and violence. A review of selected research on adolescent females with language problems residing in a correctional facility served to support a survey study and extend discussions about the need for educational leadership within this population. Ninety-six speech-language pathologists, special educators, and teachers were surveyed about their training and knowledge on the role of communication in violence. Findings suggested the majority of participants agreed on the importance of planning prevention programs. However, they did not receive training and were uncertain about providing services to students with communication disorders. Implications are provided for administrators and other school leaders to consider when planning programs
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