6,127 research outputs found
FIRE Cirrus on October 28, 1986: LANDSAT; ER-2; King Air; theory
A simultaneous examination was conducted of cirrus clouds in the FIRE Cirrus IFO-I on 10/28/86 using a multitude of remote sensing and in-situ measurements. The focus is cirrus cloud radiative properties and their relationship to cloud microphysics. A key element is the comparison of radiative transfer model calculations and varying measured cirrus radiative properties (emissivity, reflectance vs. wavelength, reflectance vs. viewing angle). As the number of simultaneously measured cloud radiative properties and physical properties increases, more sharply focused tests of theoretical models are possible
A complex speciation-richness relationship in a simple neutral model
Speciation is the "elephant in the room" of community ecology. As the
ultimate source of biodiversity, its integration in ecology's theoretical
corpus is necessary to understand community assembly. Yet, speciation is often
completely ignored or stripped of its spatial dimension. Recent approaches
based on network theory have allowed ecologists to effectively model complex
landscapes. In this study, we use this framework to model allopatric and
parapatric speciation in networks of communities and focus on the relationship
between speciation, richness, and the spatial structure of communities. We find
a strong opposition between speciation and local richness, with speciation
being more common in isolated communities and local richness being higher in
more connected communities. Unlike previous models, we also find a transition
to a positive relationship between speciation and local richness when dispersal
is low and the number of communities is small. Also, we use several measures of
centrality to characterize the effect of network structure on diversity. The
degree, the simplest measure of centrality, is found to be the best predictor
of local richness and speciation, although it loses some of its predictive
power as connectivity grows. Our framework shows how a simple neutral model can
be combined with network theory to reveal complex relationships between
speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference
The 27-28 October 1986 FIRE IFO cirrus case study: Comparison of satellite and aircraft derived particle size
Theoretical calculations predict that cloud reflectance in near infrared windows such as those at 1.6 and 2.2 microns should give lower reflectances than at visible wavelengths. The reason for this difference is that ice and liquid water show significant absorption at those wavelengths, in contrast to the nearly conservative scattering at wavelengths shorter than 1 micron. In addition, because the amount of absorption scales with the path length of radiation through the particle, increasing cloud particle size should lead to decreasing reflectances at 1.6 and 2.2 microns. Measurements at these wavelengths to date, however, have often given unpredicted results. Twomey and Cocks found unexpectedly high absorption (factors of 3 to 5) in optically thick liquid water clouds. Curran and Wu found expectedly low absorption in optically thick high clouds, and postulated the existence of supercooled small water droplets in place of the expected large ice particles. The implications of the FIRE data for optically thin cirrus are examined
Depressive Symptoms and Length of U.S. Residency Are Associated with Obesity among Low-Income Latina Mothers: A Cross-Sectional Analysis
Latinos are the largest minority population group in the United States (U.S.), and low-income Latina women are at elevated risk of depression and obesity. Thus, the prevention of these two problems is a pressing public health concern in this population. Both depressive symptoms and obesity are modifiable factors that can be addressed by culturally relevant interventions. However, the association between depressive symptoms and obesity in Latina immigrant women is not well understood. Therefore, this cross-sectional study examined the association between depressive symptoms and obesity among Latina women of childbearing age (15–44). Participants (n = 147) were low-income, predominantly immigrant Latina mothers enrolled in the Latina Mothers′ Child Feeding Practices and Style Study. Women were eligible to participate if they self-identified as Latina; were enrolled in or eligible for the Special Supplemental Nutrition Program for Women, Infants and Children program; had a child between ages two and five years; and were living in the U.S. for at least one year, and residing in Rhode Island. Enrolled participants completed a survey in their language of preference (English or Spanish) administered by bilingual interviewers. About one-third (34%) of participants were classified as having obesity (BMI ≥ 30 kg/m2), 28.3% had elevated depressive symptoms (CES-D ≥ 16), and 70.1% were immigrants. Women with elevated depressive symptoms had increased odds of having obesity (odds ratio (OR) = 2.80, 95% confidence interval (CI): 1.24–6.33). Additionally, among immigrants, length of U.S. residency was associated with increased odds of obesity (OR = 1.05, 95% CI: 1.02–1.09). Findings underscore the need for screening and culturally relevant interventions designed to address both depressive symptoms and obesity among low-income Latina women of childbearing age. Furthermore, findings highlight the importance of taking into account the length of residency in the U.S. when designing interventions targeting Latina immigrants
The 27-28 October 1986 FIRE IFO Cirrus case study: Comparison of radiative transfer theory with observations by satellite and aircraft
Observations of cirrus and altocumulus clouds during the First International Satellite Cloud Climatology Project Regional Experiment (FIRE) are compared to theoretical models of cloud radiative properties. Three tests are performed. First, LANDSAT radiances are used to compare the relationship between nadir reflectance ot 0.83 micron and beam emittance at 11.5 microns with that predicted for model calculations using spherical and nonspherical phase functions. Good agreement is found between observations and theory when water droplets dominate. Poor agreement is found when ice particles dominate, especially using scattering phase functions for spherical particles. Even when compared to a laboratory measured ice particle phase function, the observations show increased side scattered radiation relative to the theoretical calculations. Second, the anisotropy of conservatively scattered radiation is examined using simultaneous multiple angle views of the cirrus from LANDSAT and ER-2 aircraft radiometers. Observed anisotropy gives good agreement with theoretical calculations using the laboratory measured ice particle phase function and poor agreement with a spherical particle phase function. Third, Landsat radiances at 0.83, 1.65, and 2.21 microns are used to infer particle phase and particle size. For water droplets, good agreement is found with King Air FSSP particle probe measurements in the cloud. For ice particles, the LANDSAT radiance observations predict an effective radius of 60 microns versus aircraft observations of about 200 microns. It is suggested that this descrepancy may be explained by uncertainty in the imaginary index of ice and by inadequate measurements of small ice particles by microphysical probes
Recommended from our members
Transcranial magnetic stimulation (TMS) therapy for autism: an international consensus conference held in conjunction with the international meeting for autism research on May 13th and 14th, 2014
A computational framework to emulate the human perspective in flow cytometric data analysis
Background: In recent years, intense research efforts have focused on developing methods for automated flow cytometric data analysis. However, while designing such applications, little or no attention has been paid to the human perspective that is absolutely central to the manual gating process of identifying and characterizing cell populations. In particular, the assumption of many common techniques that cell populations could be modeled reliably with pre-specified distributions may not hold true in real-life samples, which can have populations of arbitrary shapes and considerable inter-sample variation.
<p/>Results: To address this, we developed a new framework flowScape for emulating certain key aspects of the human perspective in analyzing flow data, which we implemented in multiple steps. First, flowScape begins with creating a mathematically rigorous map of the high-dimensional flow data landscape based on dense and sparse regions defined by relative concentrations of events around modes. In the second step, these modal clusters are connected with a global hierarchical structure. This representation allows flowScape to perform ridgeline analysis for both traversing the landscape and isolating cell populations at different levels of resolution. Finally, we extended manual gating with a new capacity for constructing templates that can identify target populations in terms of their relative parameters, as opposed to the more commonly used absolute or physical parameters. This allows flowScape to apply such templates in batch mode for detecting the corresponding populations in a flexible, sample-specific manner. We also demonstrated different applications of our framework to flow data analysis and show its superiority over other analytical methods.
<p/>Conclusions: The human perspective, built on top of intuition and experience, is a very important component of flow cytometric data analysis. By emulating some of its approaches and extending these with automation and rigor, flowScape provides a flexible and robust framework for computational cytomics
Bloch-Nordsieck violating electroweak corrections to inclusive TeV scale hard processes
We point out that, since the colliders initial states (e+ e-,p p, p pbar, ...
) carry a definite nonabelian flavor, electroweak radiative corrections to
inclusive hard cross sections at the TeV scale are affected by peculiar
Bloch-Nordsieck violating double logs. We recall the setup of soft cancellation
theorems, and we analyze the magnitude of the noncancelling terms in the
example of electron - positron annihilation into hadrons.Comment: Minor typos corrected, references added. Final version to appear on
Phys. Rev. Let
DNA assays for genetic discrimination of three Phragmites australis subspecies in the United States
Premise: To genetically discriminate subspecies of the common reed (Phragmites australis), we developed real-time quantitative (qPCR) assays for identifying P. australis subsp. americanus, P. australis subsp. australis, and P. australis subsp. berlandieri.
Methods and Results: Utilizing study-generated chloroplast DNA sequences, we developed three novel qPCR assays. Assays were verified on individuals of each subspecies and against two non-target species, Arundo donax and Phalaris arundinacea. One assay amplifies only P. australis subsp. americanus, one amplifies P. australis subsp. australis and/or P. australis subsp. berlandieri, and one amplifies P. australis subsp. americanus and/or P. australis subsp. australis. This protocol enhances currently available rapid identification methods by providing genetic discrimination of all three subspecies.
Conclusions: The newly developed assays were validated using P. australis samples from across the United States. Application of these assays outside of this geographic range should be preceded by additional testing
Brazilian Immigrant Mothers’ Beliefs and Practices Related to Infant Feeding: A Qualitative Study
Background: Exclusive breastfeeding for the first 6 months of life and timely introduction of appropriate solid foods are important determinants of weight status in infancy and later life stages. Disparities in obesity rates among young children suggest that maternal feeding practices during the first 2 years of life may contribute to these disparities. Brazilians are a growing immigrant group in the United States, yet little research has focused on parental beliefs and behaviors affecting the health of Brazilian immigrant children in the United States.
Research aim: This study aimed to explore beliefs and infant-feeding practices of Brazilian immigrant mothers in the United States.
Methods: Focus group discussions were conducted with Brazilian immigrant mothers. Transcripts were analyzed using thematic analysis and themes categorized using the socioecological model.
Results: Twenty-nine immigrant Brazilian mothers participated in the study. Analyses revealed that all participants breastfed their infants. The majority initiated breastfeeding soon after childbirth. However, most mothers did not exclusively breastfeed. They used formula and human milk concomitantly. Family and culture influenced mothers’ infant-feeding beliefs and practices in early introduction of solid foods.
Conclusion: As the number of children in the United States growing up in families of immigrant parents increases, understanding influences on Brazilian immigrant mothers’ infant-feeding practices will be important to the development of effective interventions to promote healthy infant feeding and weight status among Brazilian children. Interventions designed for Brazilian immigrant families should incorporate an understanding of social context, family, and cultural factors to develop health promotion messages tailored to the needs of this ethnic group
- …