6,497 research outputs found
Book Review: Grit: The Power of Passion and Perseverance
I first stumbled across the research of Angela Duckworth after she was awarded the prestigious MacArthur Fellowship in 2013 for her work investigating the character traits that impact the achievement of long-term goals. So, when it was announced that she would be publishing a book in 2016, I immediately pre-ordered copy so that I could dig into her insights as soon as possible. When I received my copy of Grit: The Power of Passion and Perseverance in the mail, I was excited to crack it open… and then the self-doubt settled in. “What if, after reading the brilliant ideas of a scholar whom I highly regard, I realize that I have no grit… What if I don’t have what it takes?” I was terrified. But, I am convinced that I am not alone. In our current educational culture, one that reinforces a transactional ideology that success is unequivocally defined by test scores and GPA, what is one to do if they literally do not “measure up” to the competition? Is that the end of the road? Is success forever out of reach
Investigating Potential Risk Factors for Nursing Home Admission Associated with Individuals Enrolled in Georgia’s Community Care Services Program
This retrospective study examined records of 230 low-income elderly and disabled individuals enrolled in the Georgia Community Care Services Program (CCSP) which provides home health services in the client’s home rather than a nursing facility (NF). This study sought to determine if any common characteristics exist in program enrollees who enter a NF within one year of enrollment. Common factors found could be used to identify those who are at the highest risk for entering an NF. This knowledge could lead to reduced costs for the State of Georgia and better service for CCSP enrollees. Findings associated with NF entry include: age, Medicaid status, and monthly income. Further study is recommended to determine which common factors could be developed into a screening tool used to identify individuals at highest risk for NF entry. Specific care plans could then be developed to avoid or delay NF admission for CCSP enrollees
Orientation dependence of the acoustic backscatter for elongated zooplankton
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1993The width of the main lobe of the acoustic backscatter directivity pattern of decapod shrimp
(Palaemonetes vulgaris) is examined versus acoustic frequency. Using the distorted wave
Born approximation (DWBA) and the geometry of a prolate spheroid, an analytic formula
for the backscatter cross section as a function of orientation angle is derived. A directivity
pattern is determined from the analytic formula and the width of the main lobe (beam width)
is computed. The relationship between beamwidth and acoustic frequency is presented in
plots of beamwidth versus ka and L/λ. The model is adapted to experimental limitations of
animal motion, discrete sampling and observed side lobe levels. The backscatter directivity
patterns of live decapod shrimp, determined experimentally at frequencies between 72 and
525kHz, are presented. A non-monotonic relationship between beamwidth and frequency
is illustrated in this study. This relationship is in contrast to the monotonic relationship
exhibited when sound scatters off of an impenetrable flat plate. Reasonable agreement is
found between the theoretically predicted beamwidths and most experimental data, where
the beamwidth was more-or-less oscillatory about a mean value of 19°. The structure can at
least be partly explained by scattering theory
Merlin Phosphorylation by p21-activated Kinase 2 and Effects of Phosphorylation on Merlin Localization
The Nf2 tumor suppressor gene product merlin is related to the membrane-cytoskeleton linker proteins of the band 4.1 superfamily, including ezrin, radixin, and moesin (ERMs). Merlin is regulated by phosphorylation in a Rac/cdc42-dependent fashion. We report that the phosphorylation of merlin at serine 518 is induced by the p21-activated kinase PAK2. This is demonstrated by biochemical fractionation, use of active and dominant-negative mutants of PAK2, and immunodepletion. By using wild-type and mutated forms of merlin and phospho-directed antibodies, we show that phosphorylation of merlin at serine 518 leads to dramatic protein relocalization.
Neurofibromatosis type 2 (NF2)1 is an inherited disorder characterized by the development of Schwann cell tumors of the eighth cranial nerve. Mutations and loss of heterozygosity of theNF2 gene have been detected in NF2 patients and in various sporadic tumors, including schwannomas, meningiomas, and ependymomas (1). In further support of a role for NF2 in tumor suppression, mice heterozygous for an Nf2 mutation are predisposed to a wide variety of tumors with high metastatic potential (2). In a separate model in which Nf2 is inactivated specifically in Schwann cells, mice develop schwannomas and Schwann cell hyperplasia (3).
The longest and predominant splice form of the Nf2gene codes for a 595-amino acid protein highly similar to the band 4.1 family of proteins. It is most closely related to the ERM proteins,moesin, ezrin, and radixin. The ERM proteins are thought to function as cell membrane-cytoskeleton linkers and are localized to cortical actin structures near the plasma membrane such as microvilli, membrane ruffles, and lamellipodia (4, 5). Likewise, merlin is localized to cortical actin structures, in patterns that partially overlap with the ERMs (1). It has been proposed that intramolecular binding of the N-terminal and C-terminal domains conformationally regulates the ERM proteins by masking binding sites for interacting proteins. The ERMs can also form homodimers and heterodimers, among themselves and with merlin, adding an additional level of complexity to the regulation of these proteins (6). The recently solved crystal structure of the moesin N/C-terminal complex strengthens this model of conformational regulation (7). Given the sequence and, most likely, structural similarities of merlin to the ERM proteins, it is possible that merlin itself could be regulated in a similar fashion.
Recent studies (8, 9) have implicated additional factors in the regulation of the ERMs, including phospholipids and phosphorylation. Previous work from our group and others (10, 11) has shown that merlin is differentially phosphorylated as well and that merlin protein levels are affected by growth conditions such as cell confluency, loss of adhesion, or serum deprivation. Merlin is found in an hypophosphorylated form when the combination of cellular and environmental conditions are growth-inhibitory (10). ERMs can be phosphorylated by Rho kinase, and this phosphorylation can affect intramolecular association and cellular localization. Phosphorylation and/or phospholipids may promote the transition of the proteins to an active form by “opening” intra- and intermolecular associations. These active monomers can then bind to other interacting proteins and the actin cytoskeleton and induce actin-rich membrane projections (5,8, 12, 13). The induction of merlin phosphorylation by activated alleles of the Rho family GTPases has also been examined. Interestingly, although activated Rho did not induce noticeable phosphorylation of merlin, activated forms of Rac and cdc42 did. The site of Rac-induced phosphorylation was determined to be a serine at position 518; mutation of serine 518 results in reduced basal phosphorylation and eliminated Rac-induced phosphorylation (11).
Although Rac and cdc42 are implicated in the regulation of many pathways, they are most associated with regulation of cytoskeleton reorganization and gene expression (for recent reviews see Refs.14-16). In light of the data demonstrating that activated Rac/cdc42 leads to phosphorylation and possible inactivation of merlin, the elucidation of the responsible effector pathways and their effects on merlin function are of major importance. Understanding this regulation of merlin could lead to a more complete appreciation of the effects of merlin loss in tumors
POWERLIB: SAS/IML Software for Computing Power in Multivariate Linear Models
The POWERLIB SAS/IML software provides convenient power calculations for a wide range of multivariate linear models with Gaussian errors. The software includes the Box, Geisser-Greenhouse, Huynh-Feldt, and uncorrected tests in the "univariate" approach to repeated measures (UNIREP), the Hotelling Lawley Trace, Pillai-Bartlett Trace, and Wilks Lambda tests in "multivariate" approach (MULTIREP), as well as a limited but useful range of mixed models. The familiar univariate linear model with Gaussian errors is an important special case. For estimated covariance, the software provides confidence limits for the resulting estimated power. All power and confidence limits values can be output to a SAS dataset, which can be used to easily produce plots and tables for manuscripts.
Seeing the landscape for the trees: metrics to guide riparian shade management in river catchments
Rising water temperature (Tw) due to anthropogenic climate change may have serious consequences for river ecosystems. Conservation and/or expansion of riparian shade could counter warming and buy time for ecosystems to adapt. However, sensitivity of river reaches to direct solar radiation is highly heterogeneous in space and time, so benefits of shading are also expected to be site specific. We use a network of high-resolution temperature measurements from two upland rivers in the UK, in conjunction with topographic shade modelling, to assess the relative significance of landscape and riparian shade to the thermal behaviour of river reaches. Trees occupy 7% of the study catchments (comparable with the UK national average) yet shade covers 52% of the area and is concentrated along river corridors. Riparian shade is most beneficial for managing Tw at distances 5 to 20 km downstream from the source of the rivers where discharge is modest, flow is dominated by near-surface hydrological pathways, there is a wide floodplain with little landscape shade, and where cumulative solar exposure times are sufficient to affect Tw. For the rivers studied, we find that approximately 0.5 km of complete shade is necessary to off-set Tw by 1°C during July (the month with peak Tw) at a headwater site; whereas 1.1 km of shade is required 25 km downstream. Further research is needed to assess the integrated effect of future changes in air temperature, sunshine duration, direct solar radiation and downward diffuse radiation on Tw to help tree planting schemes achieve intended outcomes
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