Speed Reading Articles |
|
Index Index Articles Download Registration Sub vocalization Wide your span eye Words games
|
Effects of Mora Deletion, Nonword Repetition, Rapid Naming, and Visual Search Performance on Beginning Reading in JapaneseThis study examined the extent to which mora deletion (phonological analysis), nonword repetition (phonological memory), rapid automatized naming (RAN), and visual search abilities predict reading in Japanese kindergartners and first graders. Analogous abilities have been identified as important predictors of reading skills in alphabetic languages like English. In contrast to English, which is based on grapheme-phoneme relationships, the primary components of Japanese orthography are two syllabaries-hiragana and katakana (collectively termed "kana")-and a system of morphosyllabic symbols (kanji). Three RAN tasks (numbers, objects, syllabary symbols [hiragana]) were used with kindergartners, with an additional kanji RAN task included for first graders. Reading measures included accuracy and speed of passage reading for kindergartners and first graders, and reading comprehension for first graders. In kindergartners, hiragana RAN and number RAN were the only significant predictors of reading accuracy and spee d. In first graders, kanji RAN and hiragana RAN predicted reading speed, whereas accuracy was predicted by mora deletion. Reading comprehension was predicted by kanji RAN, mora deletion, and nonword repetition. Although number RAN did not contribute unique variance to any reading measure, it correlated highly with kanji RAN. Implications of these findings for research and practice are discussed. Key Words: Japanese kana, mora deletion, phonological awareness, rapid naming, reading INTRODUCTION This study examined relationships between reading skills and mora deletion (phonological analysis), nonword repetition (phonological memory), rapid automatized naming (RAN), and visual search abilities in Japanese kindergartners and first graders. Generically similar variables have been identified as important in the acquisition of word recognition, fluency, and reading comprehension in alphabetic languages like English (Badian, 1994,1995,1998; Cornwall, 1992; Meyer, Wood, Hart, & Felton, 1998a; Scarborough, 1998). In contrast to the English alphabetic system, which is based on grapheme-phoneme relationships, the primary components of Japanese orthography are two syllabaries: hiragana and katakana (collectively termed "kana"), which include approximately 51 characters each (see Kess & Miyamoto, 1999, for a review). While Japan Educational Ministry guidelines formally require hiragana instruction in first grade, hiragana is typically introduced at home, and in the first and second year of kindergarten. Hira gana symbols are used to represent high-frequency words of Japanese origin, while katakana symbols are taught later (in first grade) and are primarily used to represent foreign words and foreign names. Japanese orthography also contains a system of ideographs (kanji) that are systematically introduced, with approximately 80 characters taught by the end of first grade and about 1,000 by the end of sixth grade. Most texts incorporate both kana and kanji systems. Spoken Japanese is a CV syllable- and morabased language, with mora comprising intrasyllabic units of timing and rhythm (Leong & Tamaoka, 1998). In some words, the syllable and mora units are the same; for example, the word "umi" (sea) has two syllables and two morae. In contrast, the word "kenka" (quarrel) has two syllables and three morae because the first syllable (ken-) has two morae, a CV plus a nasal coda (Akita & Hatano, 1999, p. 214). Each Japanese syllabary character generally represents one or two mora, creating a largely transparent, syllable -based orthography (for discussions of Japanese syllabic and moraic structures, see Leong, Nitta, & Yamada, 2003; Tamaoka & Terao, 2004). Kanji characters, on the other hand, are ideographic, and often have several pronunciations and multiple meanings. Differences in transparency of written language have been suggested to lead to divergent patterns of reading acquisition and reading disabilities (Bruck, Genesee, & Caravolas, 1997). For instance, Wydell and Butterworth (1999) proposed a "hypothesis of granularity and transparency," which suggests that any language where sound-symbol correspondence is regular or transparent-such as kana characters-or any language whose orthographic units represent sounds at the word level-such as kanji characters-will produce a lower incidence of reading difficulties related to phonological analysis. An assessment of Japanese early readers with selected phonological and visual processing measures could provide insights into the key factors contributing to their reading fluency and comprehension skills. PHONOLOGICAL ANALYSIS Phonological analysis is the ability to analyze the sound structure of one`s oral language for the purposes of processing written language. In English, phonological analysis is typically assessed with tasks such as rhyming, segmentation, and deletion (Torgesen, Wagner, & Rashotte, 1994; Wagner, Torgesen, & Rashotte, 1999). English-speaking children first develop awareness of word length, then syllables in words. Eventually, their awareness progresses to onset (e.g., /b/ in /bat/) and rime (e.g., /at/ in /bat/), and finally to phonemes within syllables by around age 6 (Wagner et al., 1999). ups and downs of high-performance valvetrains, TheThis issue of National DRAGSTER includes a special section on camshafts and valvetrains, so I thought it would be appropriate to address those topics in this column. There is no doubt that a significant percentage of the improvement we have witnessed in both street-driven vehicles and race cars is directly related to improvements in the design, materials, and technology of valvetrain components. It has been said that the camshaft is the "brain" that regulates the flow of fuel and air through an internal-combustion engine by opening and closing the valves. But unlike a living brain that controls heart rate and respiration, a conventional camshaft can`t alter the valve events. There are devices that can change camshaft phasing or switch to alternate lobe profiles, but infinitely variable electronically controlled valves are still far in the future - especially systems that are capable of meeting the requirements of high-speed racing engines. Consequently, cam profiles are always a compromise. Street engines that operate at relatively low engine speeds require smooth part-throttle operation, sharp throttle response, reasonable fuel economy, and low exhaust emissions. These engines need camshaft profiles with relatively short duration. At the faster speeds achieved by high-performance and competition engines, a long-duration cam with high lift is necessary to maximize cylinder filling and scavenging during the short intervals that the valves are open, with a corresponding loss in low-speed driveability and fuel efficiency. In the early days of hot rodding, hair was short and tappets were flat. Flat tappets are inexpensive, reliable, and generally trouble-free as long as spring pressure is modest; the flat-tappet design imposes limits on how aggressively the cam lobes can operate the valves. If the ramp design is too steep, the contact area between the lobe and the foot of the lifter moves beyond the edge of the tappet, causing serious problems. Increasing the diameter of a flat tappet allows somewhat more aggressive profiles; that`s why NASCAR Winston Cup rules permit the use of .875-inch-diameter flat tappets in place of the .843-inch lifters that are standard in GM small-block engines. In fact, GM Performance Parts formerly offered a unique "mushroom" tappet with a .960-inch foot for classes that specify flat tappets. Advances in technology have made these mushroom lifters obsolete. Roller lifters have become the standard in high-performance and racing engines. The chief reasons for this move to roller lifters are a reduction in frictional losses, improved durability, and the ability to use camshaft profiles that simply aren`t feasible with flat tappets. Rollers allow short-duration seat timing with relatively quick ramps that provide good low-speed performance. They also produce a wide power band when the cam grinder takes advantage of the more rapid acceleration that is possible with roller lifters to increase the area under the lift curve. When these attributes are combined with the improved durability offered by roller lifters, it`s a win-win situation. The conventional roller tappets that have been used for decades in racing engines are a type of mechanical lifter and, consequently, they require frequent valve-- lash adjustments. The real breakthrough in lifter design for street and moderate competition applications was the marriage of roller tappets with hydraulic lifters. The new generation of hydraulic roller lifters combines the fast action of a roller tappet with the low maintenance of a hydraulic lifter. GM introduced low-friction hydraulic roller lifters in production Chevy smallblock V-8s in 1987. Tests conducted at the time showed a 3.5 percent improvement in fuel economy and a five-horsepower increase over equivalent flat-tappet cams. Even greater power gains were possible when profiles were designed to take advantage of the faster opening and closing rates offered by roller lifters. Production GM hydraulic roller lifters have a steel wheel that rotates on 18 needle bearings. This design eliminates the sliding friction of a conventional flat tappet. The contact stress on the cam lobe is greater with a roller lifter due to the wheel`s smaller, concentrated contact area. That`s why roller cams are made from steel instead of the cast iron that`s typically used for flat-tappet grinds. GM hydraulic roller-- steel roller cams are typically machined from high-carbon bar stock and induction-- hardened to ensure strength. Virtually all high-performance GM Performance Parts crate engines now use hydraulic roller lifters. Think about it: These engines produce more than 500 horsepower - and you don`t even need to lash the valves! It wasn`t too long ago that a 500-horsepower engine was an exotic, temperamental beast, but now these powerful engines can be bought over the counter. The 502-cid, 502-horsepower ZZ502, for example, employs a cam with .527-inch intake lift and .544-inch exhaust lift with duration figures of only 224 and 234 degrees, respectively, at .050-inch tappet lift. That`s really a best-of-both-worlds scenario, with the lift that`s required to make respectable horsepower and duration that`s short enough to make one of these engines streetable. Speed reading index
Copyright c 2005-2006 www.magicspeedreading.com. All Rights Reserved.
|
|
| | ||||||||||||||||