6,820 research outputs found
Mathematics in Hands-On Science for Liberal Arts Students
We describe a number of experiments from the courses called, General Science 9, part of the science program for elementary education majors at Brooklyn College. These courses provide hands-on learning experiences for students who are insecure and weak in science and mathematics. Quantitative thinking is a central element in most of the students’ work. Mathematics is taught in a concrete and intuitive way, as a direct outgrowth of their needs; first, in analysis of data, and second, in discovering underlying theory. The science program has been developed through cooperation among faculty from the School of Education and the science departments
Comparison of Periglacial Block Fields and Talus Slopes in South-Central Pennsylvania and Northern Maryland
Relict periglacial boulder fields, or block fields, are scattered across south-central Pennsylvania and northern Maryland (e.g. Potter and Moss, 1968; Denn et al 2018). This pilot study uses a combination of digital analyses using Google Earth Pro and fieldwork to investigate block fields at different scales. Fieldwork focused on two block fields, which were compared with fieldwork conducted on two talus slopes. The block fields studied were Raven Rock Hollow in Maryland and River of Rocks at Hawk Mountain in Pennsylvania, and the talus slopes were located at Catoctin Mountain, Maryland and Waggoner’s Gap, Pennsylvania. The importance of geomorphic processes on formation of block fields compared to talus slopes was examined as part of this pilot study
Fast Genome-Wide QTL Analysis Using Mendel
Pedigree GWAS (Option 29) in the current version of the Mendel software is an
optimized subroutine for performing large scale genome-wide QTL analysis. This
analysis (a) works for random sample data, pedigree data, or a mix of both, (b)
is highly efficient in both run time and memory requirement, (c) accommodates
both univariate and multivariate traits, (d) works for autosomal and x-linked
loci, (e) correctly deals with missing data in traits, covariates, and
genotypes, (f) allows for covariate adjustment and constraints among
parameters, (g) uses either theoretical or SNP-based empirical kinship matrix
for additive polygenic effects, (h) allows extra variance components such as
dominant polygenic effects and household effects, (i) detects and reports
outlier individuals and pedigrees, and (j) allows for robust estimation via the
-distribution. The current paper assesses these capabilities on the genetics
analysis workshop 19 (GAW19) sequencing data. We analyzed simulated and real
phenotypes for both family and random sample data sets. For instance, when
jointly testing the 8 longitudinally measured systolic blood pressure (SBP) and
diastolic blood pressure (DBP) traits, it takes Mendel 78 minutes on a standard
laptop computer to read, quality check, and analyze a data set with 849
individuals and 8.3 million SNPs. Genome-wide eQTL analysis of 20,643
expression traits on 641 individuals with 8.3 million SNPs takes 30 hours using
20 parallel runs on a cluster. Mendel is freely available at
\url{http://www.genetics.ucla.edu/software}
“Been there---ah, haven’t tried it that way”: A Professional Effort to Differentiate Instruction
It goes without saying that the most critical component of preparing educators lies in their ability to competently teach. Differentiation provides a framework to develop classrooms where realities of genuine student variance can be addressed with curricular realities. The author describes a professional development project that differentiated a series of teacher workshops that were designed to increase teachers’ perceived competency to differentiate instruction. The purpose here is to describe a collaboratively created and implemented professional development program designed to train staff in ways to differentiate instruction for all learners. Sample training activities, along with perceptions from participants and suggestions for realistic extensions are shared
Statistical Mechanics of the Hyper Vertex Cover Problem
We introduce and study a new optimization problem called Hyper Vertex Cover.
This problem is a generalization of the standard vertex cover to hypergraphs:
one seeks a configuration of particles with minimal density such that every
hyperedge of the hypergraph contains at least one particle. It can also be used
in important practical tasks, such as the Group Testing procedures where one
wants to detect defective items in a large group by pool testing. Using a
Statistical Mechanics approach based on the cavity method, we study the phase
diagram of the HVC problem, in the case of random regualr hypergraphs.
Depending on the values of the variables and tests degrees different situations
can occur: The HVC problem can be either in a replica symmetric phase, or in a
one-step replica symmetry breaking one. In these two cases, we give explicit
results on the minimal density of particles, and the structure of the phase
space. These problems are thus in some sense simpler than the original vertex
cover problem, where the need for a full replica symmetry breaking has
prevented the derivation of exact results so far. Finally, we show that
decimation procedures based on the belief propagation and the survey
propagation algorithms provide very efficient strategies to solve large
individual instances of the hyper vertex cover problem.Comment: Submitted to PR
Neural Processing at the Speed of Smell
AbstractOlfaction is typically described as behaviorally slow, suggesting neural processes on the order of hundreds of milliseconds to seconds as candidate mechanisms in the creation of olfactory percepts. Whereas a recent study challenged this view in suggesting that a single sniff was sufficient for optimal olfactory discrimination, a study by Abraham et al. in this issue of Neuron sets out to negate the challenge by demonstrating increased processing time for discrimination of similar versus dissimilar stimuli. Here we reconcile both studies, which in our view together support the notion of a speed-accuracy tradeoff in olfactory discriminations that are made within about 200 ms. These findings are discussed in light of the challenges related to defining olfactory perceptual similarity in nonhuman animals
Fast Genome-Wide QTL Association Mapping on Pedigree and Population Data
Since most analysis software for genome-wide association studies (GWAS)
currently exploit only unrelated individuals, there is a need for efficient
applications that can handle general pedigree data or mixtures of both
population and pedigree data. Even data sets thought to consist of only
unrelated individuals may include cryptic relationships that can lead to false
positives if not discovered and controlled for. In addition, family designs
possess compelling advantages. They are better equipped to detect rare
variants, control for population stratification, and facilitate the study of
parent-of-origin effects. Pedigrees selected for extreme trait values often
segregate a single gene with strong effect. Finally, many pedigrees are
available as an important legacy from the era of linkage analysis.
Unfortunately, pedigree likelihoods are notoriously hard to compute. In this
paper we re-examine the computational bottlenecks and implement ultra-fast
pedigree-based GWAS analysis. Kinship coefficients can either be based on
explicitly provided pedigrees or automatically estimated from dense markers.
Our strategy (a) works for random sample data, pedigree data, or a mix of both;
(b) entails no loss of power; (c) allows for any number of covariate
adjustments, including correction for population stratification; (d) allows for
testing SNPs under additive, dominant, and recessive models; and (e)
accommodates both univariate and multivariate quantitative traits. On a typical
personal computer (6 CPU cores at 2.67 GHz), analyzing a univariate HDL
(high-density lipoprotein) trait from the San Antonio Family Heart Study
(935,392 SNPs on 1357 individuals in 124 pedigrees) takes less than 2 minutes
and 1.5 GB of memory. Complete multivariate QTL analysis of the three
time-points of the longitudinal HDL multivariate trait takes less than 5
minutes and 1.5 GB of memory
Finding and Dating Cathlapotle
The people of the Cathlapotle town played a significant role in the fur trade era history of the Lower Columbia River, including Lewis and Clark’s visit on March 29th, 1806. Archaeologists and others have sought the town’s location for years. Long-term research has established that archaeological site 45CL1 on the US Fish and Wildlife Refuge near Ridgefield, Washington is Cathlapotle. This determination is based on the close match between site details with various ethnohistoric accounts of Cathlapotle. The site was occupied by ca. AD 1450 and probably moved there from another nearby location. It was abandoned sometime in the 1830s or 1840s. This chronology is based on 54 radiocarbon dates, historic trade goods including glass beads and ceramics, and documentary accounts
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