Advantages and Disadvantages of Separate Norms for African Americans

This article provides a broad review of research around black political representation in Congress and state legislatures. We begin by exploring trends in black representation in legislative bodies from Reconstruction until 2018. We then discuss controversies around the creation of majority-minority districts and the advantages and disadvantages of these districts for African Americans. Our investigation considers the legislative and empowerment benefits that blacks gain from being represented by someone who looks like them. We conclude by discussing potential areas for future research around descriptive representation and assess how growing diversity in the 116th Congress may matter for the numerous challenges the black community faces.

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Cryogenic atomic force microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084570 ◽

1991 ◽

Vol 49 ◽

pp. 54-55

Author(s):

K. A. Fisher ◽

M. G. L. Gustafsson ◽

M. B. Shattuck ◽

J. Clarke

Keyword(s):

Room Temperature ◽

Rapid Freezing ◽

Cryogenic Temperatures ◽

Soft Or ◽

Electrically Conductive ◽

Force Microscopy ◽

Flexible Molecules ◽

Advantages And Disadvantages ◽

Atomic Force ◽

Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

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A conduction-cooled stage for high-resolution Cryo-SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100131048 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1282-1283

Author(s):

John G. Sheehan

Keyword(s):

High Resolution ◽

Liquid Nitrogen ◽

Mechanical Stability ◽

Cooling System ◽

Cold Trap ◽

Nitrogen Gas ◽

Particulate Suspensions ◽

Advantages And Disadvantages ◽

Convection Cooling ◽

Styrene Butadiene

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

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Computer simulations for the TEM bend contour technique

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163137 ◽

1996 ◽

Vol 54 ◽

pp. 134-135

Author(s):

Vladimir Yu. Kolosov ◽

Anders R. Thölén

Keyword(s):

Computer Simulations ◽

Real Space ◽

Advantages And Disadvantages ◽

Short Overview ◽

Diffraction Contrast ◽

Beam Method ◽

Convergent Beam ◽

Contour Technique

In this paper we give a short overview of two TEM applications utilizing the extinction bend contour technique (BC) giving the advantages and disadvantages; especially we consider two areas in which the BC technique remains unique. Special attention is given to an approach including computer simulations of TEM micrographs.BC patterns are often observed in TEM studies but are rarely exploited in a serious way. However, this type of diffraction contrast was one of the first to be used for analysis of imperfections in crystalline foils, but since then only some groups have utilized the BC technique. The most extensive studies were performed by Steeds, Eades and colleagues. They were the first to demonstrate the unique possibilities of the BC method and named it real space crystallography, which developed later into the somewhat similar but more powerful convergent beam method. Maybe, due to the difficulties in analysis, BCs have seldom been used in TEM, and then mainly to visualize different imperfections and transformations.

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Faculty practice: advantages and disadvantages

Journal of Dental Education ◽

10.1002/j.0022-0337.1978.42.10.tb01216.x ◽

1978 ◽

Vol 42 (10) ◽

pp. 576-578

Author(s):

J Klooster

Keyword(s):

Advantages And Disadvantages

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Aging and Ethnicity: Communication Services for Older African-Americans

Perspectives on Communication Disorders and Sciences in Culturally and Linguistically Diverse Populations ◽

10.1044/cds3.2.3 ◽

1997 ◽

Vol 3 (2) ◽

pp. 3-5

Author(s):

Joyce L. Harris

Keyword(s):

African Americans ◽

Communication Services ◽

Older African Americans

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Instrumental Assessment in Cleft Palate Care

Perspectives on Speech Science and Orofacial Disorders ◽

10.1044/ssod23.2.49 ◽

2013 ◽

Vol 23 (2) ◽

pp. 49-61 ◽

Cited By ~ 3

Author(s):

Jamie Perry ◽

Graham Schenck

Keyword(s):

Cleft Palate ◽

New Developments ◽

Perceptual Evaluation ◽

Advantages And Disadvantages ◽

Instrumental Assessment ◽

Speech Language Pathologist ◽

Hypernasal Speech ◽

Perceptual Assessment ◽

Velopharyngeal Function ◽

And Function

Despite advances in surgical management, it is estimated that 20–30% of children with repaired cleft palate will continue to have hypernasal speech and require a second surgery to create normal velopharyngeal function (Bricknell, McFadden, & Curran, 2002; Härtel, Karsten, & Gundlach, 1994; McWilliams, 1990). A qualitative perceptual assessment by a speech-language pathologist is considered the most important step of the evaluation for children with resonance disorders (Peterson-Falzone, Hardin-Jones, & Karnell, 2010). Direct and indirect instrumental analyses should be used to confirm or validate the perceptual evaluation of an experienced speech-language pathologist (Paal, Reulbach, Strobel-Schwarthoff, Nkenke, & Schuster, 2005). The purpose of this article is to provide an overview of current instrumental assessment methods used in cleft palate care. Both direct and indirect instrumental procedures will be reviewed with descriptions of the advantages and disadvantages of each. Lastly, new developments for evaluating velopharyngeal structures and function will be provided.

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