Context.
Understanding the source of sub-stellar polarimetric observations in the optical and near-infrared is key to characterizing sub-stellar objects and developing potential diagnostics for ...determining properties of their atmospheres. Differential scattering from a population of aligned, non-spherical dust grains is a potential source of polarization that could be used to determine geometric properties of the dust clouds.
Aims.
This paper addresses the problem of the spheroidal growth of dust grains in electrically activated sub-stellar atmospheres. It presents the novel application of a mechanism whereby non-spherical, elongated dust grains can be grown via plasma deposition as a consequence of the surface electric field effects of charged dust grains.
Methods.
We numerically solve the differential equations governing the spheroidal growth of charged dust grains via plasma deposition as a result of surface electric field effects in order to determine how the dust eccentricity and the dust particle eccentricity distribution function evolve with time. From these results, we determine the effect of spheroidal dust on the observed linear polarization.
Results.
Numerical solutions show that
e
≈ 0.94 defines a watershed eccentricity, where the eccentricity of grains with an initial eccentricity less than (greater than) this value decreases (increases) and spherical (spheroidal) growth occurs. This produces a characteristic bimodal eccentricity distribution function yielding a fractional change in the observed linear polarization of up to ≈0.1 corresponding to dust grains of maximal eccentricity at wavelengths of ≈1
μ
m, consistent with the near infrared observational window. Order of magnitude calculations indicate that a population of aligned, spheroidal dust grains can produce degrees of polarization
P
≈ (10
−2
− 1%) consistent with observed polarization signatures.
Conclusions.
The results presented here are relevant to the growth of non-spherical, irregularly shaped dust grains of general geometry where non-uniform surface electric field effects of charged dust grains are significant. The model described in this paper may also be applicable to polarization from galactic dust and dust growth in magnetically confined plasmas.
Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet and dry seasons in ...Central Amazonia to show that plant phenology varies strongly across vertical strata in old-growth forests, but is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we find that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests lost plant material. In contrast, the understory greened up with increased light availability driven by the upper canopy loss, alongside increases in solar radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures in forest edges exacerbated the upper canopy losses of large trees throughout the dry season, whereas the understory in these light-rich environments was less dependent on the altered upper canopy structure. Our findings reveal a strong influence of edge effects on phenological controls in wet forests of Central Amazonia.
In this 14-d cage study, the effects of feed form (mash and crumble) and 6 coarse ground corn (CC) inclusions 0, 10, 20, 30, 40, and 50% CC that replaced fine corn (FC) on broiler live performance, ...BW uniformity, gizzard weight, excreta nitrogen, and particle size preference were investigated. The geometric mean diameter by mass (dgw) of mash diets increased from 422 μm to 431, 471, 509, 542, and 640 μm, respectively, as the percentage of CC increased. Feed intake and BW were decreased by CC and mash at 7 d. Interactions between feed form and CC were observed for feed conversion ratio (FCR) at 7 d of age (P < 0.01), and feed intake (P < 0.05), BW (P < 0.01), and gizzard weight (P < 0.01) at 14 d of age. Feed intake for all CC inclusions in crumble diets was similar and exceeded (P < 0.01) that of mash diets at 14 d. Among mash diets, the 10 and 30% CC feed intake was greater (P < 0.05) than 40 and 50% CC with 0 and 20% CC intermediate. Crumble diets produced a similar BW but greater 14-d BW than mash diets (P < 0.01). Within mash diets, 40 and 50% CC produced a smaller BW (P < 0.01). The FCR at 7 d of CC inclusions in crumble diets was improved (P < 0.01) versus the same CC in mash diets. Within mash diets, 40% CC performed poorer than 0, 10, 20, and 30% CC diets with 50% CC diet intermediate (P < 0.01). Crumble diets improved FCR at 14 d, but CC worsened FCR. Gizzard weight at 14 d was not affected by CC in crumble diets, while it increased with CC in mash diets (P < 0.01). Excreta nitrogen was increased (P < 0.01) by crumble diets. These data demonstrated that pelleting and crumbling reduced the impact of CC, produced a more consistent feed intake, and reduced selective feeding, and that CC stimulated gizzard weight in a linear manner in mash diets.
Cardiac surgery is the most common setting for massive transfusion in medically advanced countries. Studies of massive transfusion after injury suggest that the ratios of administered plasma and ...platelets (PLT) to red blood cells (RBCs) affect mortality. Data from the Red Cell Storage Duration Study (RECESS), a large randomized trial of the effect of RBC storage duration in patients undergoing complex cardiac surgery, were analyzed retrospectively to investigate the association between blood component ratios used in massively transfused patients and subsequent clinical outcomes.
Massive transfusion was defined as those who had ≥6 RBC units or ≥8 total blood components. For plasma, high ratio was defined as ≥1 plasma unit:1 RBC unit. For PLT transfusion, high ratio was defined as ≥0.2 PLT doses:1 RBC unit; PLT dose was defined as 1 apheresis PLT or 5 whole blood PLT equivalents. The clinical outcomes analyzed were mortality and the change in the Multiple Organ Dysfunction Score (ΔMODS) comparing the preoperative score with the highest composite score through the earliest of death, discharge, or day 7. Outcomes were compared between patients transfused with high and low ratios. Linear and Cox regression were used to explore relationships between predictors and continuous outcomes and time to event outcomes.
A total of 324 subjects met the definition of massive transfusion. In those receiving high plasma:RBC ratio, the mean (SE) 7- and 28-day ΔMODS was 1.24 (0.45) and 1.26 (0.56) points lower, (P = .007 and P = .024), respectively, than in patients receiving lower ratios. In patients receiving high PLT:RBC ratio, the mean (SE) 7- and 28-day ΔMODS were 1.55 (0.53) and 1.49 (0.65) points lower (P = .004 and P = .022), respectively. Subjects who received low-ratio plasma:RBC transfusion had excess 7-day mortality compared with those who received high ratio (7.2% vs 1.7%, respectively, P = .0318), which remained significant at 28 days (P = .035). The ratio of PLT:RBCs was not associated with differences in mortality.
This analysis found that in complex cardiac surgery patients who received massive transfusion, there was an association between the composition of blood products used and clinical outcomes. Specifically, there was less organ dysfunction in those who received high-ratio transfusions (plasma:RBCs and PLT:RBCs), and lower mortality in those who received high-ratio plasma:RBC transfusions.
HD 53143 is a mature Sun-like star and host to a broad disk of dusty debris, including a cold outer ring of planetesimals near 90 au. Unlike most other inclined debris disks imaged at visible ...wavelengths, the cold disk around HD 53143 appears as disconnected "arcs" of material, with no forward-scattering side detected to date. We present new, deeper Hubble Space Telescope Imaging Spectrograph coronagraphic observations of the HD 53143 debris disk and show that the forward-scattering side of the disk remains undetected. By fitting our KLIP-reduced observations via forward modeling with an optically thin disk model, we show that fitting the visible wavelength images with an azimuthally symmetric disk with unconstrained orientation results in an unphysical edge-on orientation that is at odds with recent ALMA observations, while constraining the orientation to that observed by ALMA results in nearly isotropically scattering dust. We show that the HD 53143 host star exhibits significant stellar variations due to spot rotation and revisit age estimates for this system.
The quantification of total starch content (TS) or degree of starch gelatinization (DG) in animal feed is always challenging because of the potential interference from other ingredients. In this ...study, the differences in TS or DG measurement in pelleted swine feed due to variations in analytical methodology were quantified. Pelleted swine feed was used to create 6 different diets manufactured with various processing conditions in a 2 × 3 factorial design (2 conditioning temperatures, 77 or 88°C, and 3 conditioning retention times, 15, 30, or 60 s). Samples at each processing stage (cold mash, hot mash, hot pelletized feed, and final cooled pelletized feed) were collected for each of the 6 treatments and analyzed for TS and DG. Two different methodologies were evaluated for TS determination (the AOAC International method 996.11 vs. the modified glucoamylase method) and DG determination (the modified glucoamylase method vs. differential scanning calorimetry DSC). For TS determination, the AOAC International method 996.11 measured lower TS values in cold pellets compared with the modified glucoamylase method. The AOAC International method resulted in lower TS in cold mash than cooled pelletized feed, whereas the modified glucoamylase method showed no significant differences in TS content before or after pelleting. For DG, the modified glucoamylase method demonstrated increased DG with each processing step. Furthermore, increasing the conditioning temperature and time resulted in a greater DG when evaluated by the modified glucoamylase method. However, results demonstrated that DSC is not suitable as a quantitative tool for determining DG in multicomponent animal feeds due to interferences from nonstarch transformations, such as protein denaturation.
Many people with aphasia and people without brain injury talk to themselves in their heads, i.e., have "inner speech." Inner speech may be more preserved compared with spoken speech for some people ...with aphasia and may serve a variety of functions (e.g., emotion regulation), which motivates us to provide a high-fidelity characterization of it. Researchers have used multiple methods to measure this internal phenomenon in the past, which we combine here for the first time in a single study.
We compare performance between individuals with and without aphasia on inner speech tasks that assess inner speech "in-the-moment" to general subjective impressions of inner speech to tease apart the relationship of aphasia severity to inner speech.
Twenty people with mild-moderate aphasia and twenty neurotypical controls completed several inner speech tasks, including objective silent rhyme judgements (picture, written, and auditory), subjective reports of inner speech during naming, and subjective rating scales about inner speech experience more generally.
In-the-moment inner speech during silent rhyming tasks was associated with aphasia severity only for picture and written rhyming but not auditory rhyming. In-the-moment inner speech reports during silent naming were not associated with aphasia severity, nor were the subjective ratings about general inner speech experience. Individuals with and without aphasia demonstrated a variety of subjective general inner speech experiences, demonstrating heterogeneity of this phenomenon more broadly.
Methods of measuring inner speech complement each other and speak to different facets of the inner speech phenomenon, and clinicians and researchers must carefully choose the method(s) that will provide the information about inner speech that they desire.
New multi-roll coronagraphic images of the HD181327 debris disk obtained using the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope reveal the debris ring in its entirety at ...high signal-to-noise ratio and unprecedented spatial resolution. We present and apply a new multi-roll image processing routine to identify and further remove quasi-static point-spread function-subtraction residuals and quantify systematic uncertainties. We also use a new iterative image deprojection technique to constrain the true disk geometry and aggressively remove any surface brightness asymmetries that can be explained without invoking dust density enhancements/deficits. The measured empirical scattering phase function for the disk is more forward scattering than previously thought and is not well-fit by a Henyey-Greenstein function. The empirical scattering phase function varies with stellocentric distance, consistent with the expected radiation pressured-induced size segregation exterior to the belt. Within the belt, the empirical scattering phase function contradicts unperturbed debris ring models, suggesting the presence of an unseen planet. The radial profile of the flux density is degenerate with a radially varying scattering phase function; therefore estimates of the ring's true width and edge slope may be highly uncertain. We detect large scale asymmetries in the disk, consistent with either the recent catastrophic disruption of a body with mass >1% the mass of Pluto, or disk warping due to strong interactions with the interstellar medium.
Satellite observations of Amazon forests show seasonal and interannual variations, but the underlying biological processes remain debated.
Here we combined radiative transfer models (RTMs) with field ...observations of Amazon forest leaf and canopy characteristics to test three hypotheses for satellite-observed canopy reflectance seasonality: seasonal changes in leaf area index, in canopy-surface leafless crown fraction and/or in leaf demography.
Canopy RTMs (PROSAIL and FLiES), driven by these three factors combined, simulated satellite-observed seasonal patterns well, explaining c. 70% of the variability in a key reflectance-based vegetation index (MAIAC EVI, which removes artifacts that would otherwise arise from clouds/aerosols and sun–sensor geometry). Leaf area index, leafless crown fraction and leaf demography independently accounted for 1, 33 and 66% of FLiES-simulated EVI seasonality, respectively. These factors also strongly influenced modeled near-infrared (NIR) reflectance, explaining why both modeled and observed EVI, which is especially sensitive to NIR, captures canopy seasonal dynamics well.
Our improved analysis of canopy-scale biophysics rules out satellite artifacts as significant causes of satellite-observed seasonal patterns at this site, implying that aggregated phenology explains the larger scale remotely observed patterns. This work significantly reconciles current controversies about satellite-detected Amazon phenology, and improves our use of satellite observations to study climate–phenology relationships in the tropics.
We design and analyze a method to extract secret keys from the randomness inherent to wireless channels. We study a channel model for a multipath wireless channel and exploit the channel diversity in ...generating secret key bits. We compare the key extraction methods based both on entire channel state information (CSI) and on single channel parameter such as the received signal strength indicators (RSSI). Due to the reduction in the degree-of-freedom when going from CSI to RSSI, the rate of key extraction based on CSI is far higher than that based on RSSI. This suggests that exploiting channel diversity and making CSI information available to higher layers would greatly benefit the secret key generation. We propose a key generation system based on low-density parity-check (LDPC) codes and describe the design and performance of two systems: one based on binary LDPC codes and the other (useful at higher signal-to-noise ratios) based on four-ary LDPC codes.
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