Development of kelp rockfish, Sebastes atrovirens (Jordan and Gilbert 1880), and brown rockfish, S. auriculatus (Girard 1854), from birth to pelagic juvenile stage, with notes on early larval development of black-and-yellow rockfish, S. chrysomelas (Jordan and Gilbert 1880), reared in the laboratory (Pisces: Sebastidae).

Larval kelp (Sebastes atrovirens), brown (S. auriculatus), and blackand-yellow (S. chrysomelas) rockfish were reared from known adults, to preflexion stage, nine days after birth for S. chrysomelas, to late postflexion stage for S. atrovirens, and to pelagic juvenile stage for S. auriculatus. Larval S. atrovirens and S. chrysomelas were about 4.6 mm body length (BL) and S. auriculatus about 5.2 mm BL at birth. Both S. atrovirens and S. auriculatus underwent notochord flexion at about 6–9 mm BL. Sebastes atrovirens transform to the pelagic juvenile stage at about 14–16 mm BL and S. auriculatus transformed at ca. 25 mm BL. Early larvae of all three species were characterized by melanistic pigment dorsally on the head, on the gut, on most of the ventral margin of the tail, and in a long series on the dorsal margin of the tail. Larval S. atrovirens and S. auriculatus developed a posterior bar on the tail during the flexion or postflexion stage. In S. atrovirens xanthic pigment resembled the melanistic pattern throughout larval development. Larval S. auriculatus lacked xanthophores except on the head until late preflexion stage, when a pattern much like the melanophore pattern gradually developed. Larval S. chrysomelas had extensive xanthic pigmentation dorsally, but none ventrally, in preflexion stage. All members of the Sebastes subgenus Pteropodus (S. atrovirens, S. auriculatus, S. carnatus, S. caurinus, S. chrysomelas, S. dalli, S. maliger, S. nebulosus, S. rastrelliger) are morphologically similar and all share the basic melanistic pigment pattern described here. Although the three species reared in this study can be distinguished on the basis of xanthic pigmentation, it seems unlikely that it will be possible to reliably identify field-collected larvae to species using traditional morphological and melanistic pigmentation characters. (PDF file contains 36 pages.

To Game or Not to Game? How Using Massively Multiplayer Online Games Helped Motivation and Performance in a College Writing Course: A Mixed Methods Study

The use of Massively Multiplayer Online Games or MMOGs is receiving attention in the educational world due to increased availability of such games, a growing consumer base, and the proven benefits of video games as engagement tools. MMOGs that have been known to possess a significantly high capacity to keep users involved over sustained periods, which gives them the potential to enhance learning experiences and performances. However, most available studies on MMOGs do not discuss relationships between MMOG use and performance outcomes in Higher Education. Additionally, majority of such studies focus on examining a single MMOG, providing limited scopes of understanding the benefits of multiple MMOGs as educational tools. Using a sample of 32 students, this mixed-methods study investigates and supports how inserting MMOGs within an undergraduate Online English Composition section helped improve learners’ performance and engagement. Practitioner and future research implications are also discussed

Instructional Design and Strategies for Multicultural Education: A Qualitative Case Study

With more people moving abroad for education and work, many countries are becoming multicultural in population. Hence, developing multicultural attitudes is becoming imperative to prevent negative thoughts and feelings toward minorities that may translate into discriminatory behaviors toward them. One way to ensure this is through multicultural education. The aim of multicultural education is to ensure that students from diverse racial, ethnic, and social-class groups will experience educational equality. This qualitative case study analyzes the course design and instructional strategies implemented by a professor in a multicultural education course offered in a U.S. university. We have examined how the professor taught about multicultural education, ensured educational equality in her class, and also successfully produced multicultural attitudes among her students

A non-local computational boundary condition for duct acoustics

A non-local boundary condition is formulated for acoustic waves in ducts without flow. The ducts are two dimensional with constant area, but with variable impedance wall lining. Extension of the formulation to three dimensional and variable area ducts is straightforward in principle, but requires significantly more computation. The boundary condition simulates a nonreflecting wave field in an infinite duct. It is implemented by a constant matrix operator which is applied at the boundary of the computational domain. An efficient computational solution scheme is developed which allows calculations for high frequencies and long duct lengths. This computational solution utilizes the boundary condition to limit the computational space while preserving the radiation boundary condition. The boundary condition is tested for several sources. It is demonstrated that the boundary condition can be applied close to the sound sources, rendering the computational domain small. Computational solutions with the new non-local boundary condition are shown to be consistent with the known solutions for nonreflecting wavefields in an infinite uniform duct

Evaluation of several non-reflecting computational boundary conditions for duct acoustics

Several non-reflecting computational boundary conditions that meet certain criteria and have potential applications to duct acoustics are evaluated for their effectiveness. The same interior solution scheme, grid, and order of approximation are used to evaluate each condition. Sparse matrix solution techniques are applied to solve the matrix equation resulting from the discretization. Modal series solutions for the sound attenuation in an infinite duct are used to evaluate the accuracy of each non-reflecting boundary conditions. The evaluations are performed for sound propagation in a softwall duct, for several sources, sound frequencies, and duct lengths. It is shown that a recently developed nonlocal boundary condition leads to sound attenuation predictions considerably more accurate for short ducts. This leads to a substantial reduction in the number of grid points when compared to other non-reflecting conditions

Hubble and Spitzer Observations of an Edge-on Circumstellar Disk around a Brown Dwarf

We present observations of a circumstellar disk that is inclined close to edge-on around a young brown dwarf in the Taurus star-forming region. Using data obtained with SpeX at the NASA Infrared Telescope Facility, we find that the slope of the 0.8-2.5 um spectrum of the brown dwarf 2MASS J04381486+2611399 cannot be reproduced with a photosphere reddened by normal extinction. Instead, the slope is consistent with scattered light, indicating that circumstellar material is occulting the brown dwarf. By combining the SpeX data with mid-IR photometry and spectroscopy from the Spitzer Space Telescope and previously published millimeter data from Scholz and coworkers, we construct the spectral energy distribution for 2MASS J04381486+2611399 and model it in terms of a young brown dwarf surrounded by an irradiated accretion disk. The presence of both silicate absorption at 10 um and silicate emission at 11 um constrains the inclination of the disk to be ~70 deg, i.e. ~20 deg from edge-on. Additional evidence of the high inclination of this disk is provided by our detection of asymmetric bipolar extended emission surrounding 2MASS J04381486+2611399 in high-resolution optical images obtained with the Hubble Space Telescope. According to our modeling for the SED and images of this system, the disk contains a large inner hole that is indicative of a transition disk (R_in~58 R_star~0.275 AU) and is somewhat larger than expected from embryo ejection models (R_out=20-40 AU vs. R_out<10-20 AU).Comment: The Astrophysical Journal, in pres

Integrin α2β1 mediates outside-in regulation of platelet spreading on collagen through activation of Src kinases and PLCγ2

Collagen plays a critical role in hemostasis by promoting adhesion and activation of platelets at sites of vessel injury. In the present model of platelet–collagen interaction, adhesion is mediated via the inside-out regulation of integrin α2β1 and activation through the glycoprotein VI (GPVI)–Fc receptor (FcR) γ-chain complex. The present study extends this model by demonstrating that engagement of α2β1 by an integrin-specific sequence from within collagen or by collagen itself generates tyrosine kinase–based intracellular signals that lead to formation of filopodia and lamellipodia in the absence of the GPVI–FcR γ-chain complex. The same events do not occur in platelet suspensions. α2β1 activation of adherent platelets stimulates tyrosine phosphorylation of many of the proteins in the GPVI–FcR γ-chain cascade, including Src, Syk, SLP-76, and PLCγ2 as well as plasma membrane calcium ATPase and focal adhesion kinase. α2β1-mediated spreading is dramatically inhibited in the presence of the Src kinase inhibitor PP2 and in PLCγ2-deficient platelets. Spreading is abolished by chelation of intracellular Ca2+. Demonstration that adhesion of platelets to collagen via α2β1 generates intracellular signals provides a new insight into the mechanisms that control thrombus formation and may explain the unstable nature of β1-deficient thrombi and why loss of the GPVI–FcR γ-chain complex has a relatively minor effect on bleeding