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Minimum competency testing has become both a political and an educational issue in many states. However, its impact on handicapped students for high school graduation has not been adequately examined. This article reports on a survey conducted of states involved in minimum competency testing activities. Data concerning the policies of these states regarding testing requirements, techniques of testing handicapped students, and provisions for remediation of handicapped students who fail competency tests are reported and discussed and particular areas of concern are delineated.

Despite the fact that the field of learning disabilities has grown dramatically in recent years, many questions remain unanswered or disputed. In the absence of a clear definition of learning disabilities, the authors suggest that it has become an educational simile with children described as “like a learning disabled child.” It is postulated that the learning disabled label has become reflective of a problem related more to social structure than to children. It is time that the optimism orginally connected with the term should lead to greater attention to individual needs and less emphasis on categorical concerns.

We performed a population-based case-control study of risk factors for primary invasive Haemophilus influenzae type b (Hib) disease in metropolitan Atlanta from July 1, 1983, through June 30, 1984. Active surveillance identified 102 cases in children less than 5 years of age, 89 of whom lived in households with telephones. We used random digit dialing to select 530 controls who were postmatched to cases by age. Multivariate analysis showed a significant association between Hib disease and two independent exposure factors, household crowding (odds ratio (OR) 2.7, 95% confidence limits (CL) 1.3 to 5.6) and day-care attendance. For day-care attendance, relative risk was highest in 2- to 5-month-old infants (OR 17.7, 95% CL 5.8 to 54.4) and declined to 9.4 (4.3 to 20.9) at ages 6 to 11 months, 5.0 (2.7 to 9.3) at 12 to 23 months, 2.7 (1.3 to 5.5) at 24 to 35 months, and 1.4 (0.5 to 4.0) in 36- to 59-month-old children. Fifty percent of all invasive Hib disease that occurred during the study period was attributable to exposure to day-care; the attributable risk for household crowding was 18%. Dose-response effects were observed for hours per week of day-care attendance and extent of household crowding. Breast-feeding was protective for infants less than 6 months of age (OR 0.08, 95% CL 0.01 to 0.59). After controlling for socioeconomic and other confounding factors, we could demonstrate no effect of black race on cumulative risk of invasive Hib disease. Our study defines high-risk groups and provides a population-based model of the interrelationship between risk factors associated with invasive Hib disease.

The products of the reaction between methylamine and trialkylaluminiums were studied by molecular weight determinations as well as by infrared and nuclear magnetic resonance spectroscopy. Stereoisomers of (R2A1NHR)3 are indicated. The reactions of phosphine adducts of organoaluminium compounds were studied and an order of base strength with respect to triethylaluminium was established by displacement reactions. Polymers of composition (RA1PR)x were prepared but crystalline products were obtained. Aluminium-nitrogen seem to be more stable than corresponding aluminium- phosphorus frameworks.

Treatment with pmdeta [pmdeta = Me2N(CH2)2NMe(CH2)2NMe(CH2)2NMe2] in toluene of [Li(thf)4][Li{C(SiMe3)3}2](thf = tetrahydrofuran) containing LiCl has given [(pmdeta)Li(µ-Cl]Li(pmdeta)][Li{C(SiMe3)3}2], in which the chlorine-centred cation is linear.

The quadrupole moment of /sup 6/Li is smaller than that of any other isotope, so /sup 6/Li behaves in isotropic solutions like a spin-1/2 nucleus, and in environments where signals from /sup 7/Li are broad and difficult to observe, /sup 6/Li may give narrow lines. Whereas quadrupole relaxation is dominant for /sup 7/Li, dipolar interactions with the nearest protons dominate relaxation of /sup 6/Li. It should thus be possible by gated decoupling experiments with careful selective narrow-band irradiation of the /sup 1/H spectrum to use the nuclear Overhauser effect (NOE)/sup 4/ to identify those protons in an organolithium compound or lithium hydride that are close to a /sup 6/Li nucleus, and we have shown the validity of this approach by examining the structure in solution of some alkyltrihydrometalates (compounds of a type important as reducing agents in organic synthesis).

IODINE in seawater is present as iodate (IO3−) and as iodide (I−)1–3. Although there is some uncertainty in the true redox potentials of natural waters4, the thermodynamically stable species of iodine in seawater, and in river waters which are well oxygenated, is iodate5–7. We have studied an estuary to determine the distribution of iodine species as a function of salinity, and examined the results for evidence of interconversion of species in the estuary. We report here that iodide is the dominant form in river water and is oxidised to the thermodynamically stable iodate in the sea, not in the estuary.

The compounds [{(Me2PhSi)3CZnOH}2] and [O{(Me3Si)3Cln}4(OH)6] have been shown by X-ray diffraction to have structures based on four-membered M2O2-rings (M = Zn or ln).

Contends that R. E. Fancher's (see record 1988-31600-001) evidence concerning intentions behind retouching of photographs of the Kallikaks in H. H. Goddard's (1912) study of mental retardation and heredity fall far short of challenging S. J. Gould's (1981) findings on the same topic. Further, Fancher's citation may misrepresent J. D. Smith's (1985) work on Goddard.

The reaction between tris(trimethylsilyl)methyl-lithium and manganese(II) or cobalt(II) chloride yields lithium salts with chloride-bridged polynuclear anions; the manganese compound [Li(thf)4][{(Me3Si)3C}3Mn3Cl4(thf)](thf = tetrahydrofuran) has been characterised by an X-ray study.

Molecules of the compound [(thf)3Li(µ-H)3 BC(SiMe2Ph)3], (thf = terahydrofuran) made by reduction of difluoro-{tris(dimethylphenylsilyl)methyl}boron with LiAlH4, have been shown by X-ray crystallography to have almost C3 symmetry, with tridentate bridges between alkyltrihydroborate and lithium.

The hydride (Me3Si)3C[graphic omitted])(H)C(SiMe3)3(1)(thf = tetrahydrofuran) has been structurally characterised; there are probably single hydrogen bridges between In and Li and between In and In in the crystal, and the structure is probably preserved in solution in toluene or thf.

The molecule (MeAlNMe)7 has a cage structure; each aluminium and nitrogen atom is four-co-ordinate, and is bound to one methyl group and three atoms within the cage.

WE have developed a method for the determination of traces of mercury, and have applied it to the tidal reaches of the River Thames. This article reports our observations of the concentrations of mercury and its partition between dissolved forms and that adsorbed on suspended particulate matter.

THERE are few reported measurements of the concentration of tin in seawater or the tissues of marine organisms. Noddack and Noddack1 gave a value of 3 µg of Sn/l. for water from the Gullmarfjord, Sweden, and Shimizu and Ogata2 reported a concentration of 1.8 µg/l, for water from the Japan coast. Hamaguchi et al.3, using neutron activation analysis, found between 0.30 and 1.22 µg/l. (mean 0.81 µg/l.) in samples from the north-west Pacific. The most reliable information about the occurrence of tin in organisms was provided by Black and Mitchell4 for marine algae which contained 0.03–3.8 µg of Sn/g dry weight, and by Hamaguchi et al.3, who found 0.7–2.9 µg/g dry weight in three animal species from Tokyo Bay.

Only at 245 °C is the rate of the thermal decomposition of (Me2PhSi)3CHgCH2Ph in diphenyl ether comparable with that of (PhCH2)2Hg at 150 °C; it is suggested that this may be because within the collisionally energized molecule there is only slow transmission of energy through the metal atom.

The product of the reaction between MnCl2 and tris(trimethylsilyl)methyl-lithium in 1:2 molar ratio in tetrahydrofuran is the monomeric species [Mn{C(SiMe3)3}2], the first two-co-ordinate manganese compound to be characterized.

A crystal structure determination on the tetrahydrofuran (thf) adduct of tris (phenyldimethylsilyl) methyl-lithium has shown it to be a monomeric species [Li{C(SiMe2Ph)3}(thf)] in which the lithium is covalently bonded to oxygen and to the central carbon of the (Me2PhSi)3C group and interacts strongly with the ipso carbon atom of one of the phenyl groups without significantly distorting the hybridization at that atom.

Reactions of (Me3Si)2C(SnMe3)(SiMe2l) with AgY (Y = O2CMe, O2CCF3, or O3SCF3) give exclusively (Me3Si)3CSnMe2Y; i.e. 1,3-migration of an Me group from an Sn to an Si atom occurs, apparently within an intermediate cation in which an Me group bridges between these atoms.

Trimethylgallium reacts with hydrides [(C5H5)W(CO)2LH][(6) L = CO or (7) L = PPh3] to give [(C5H5)W(CO)2L-(GaMe2)][(2) L = CO or (5) L = PPh3]. (2) Decomposes in hot hydrocarbon solution with formation of [{(C5H5)W(CO)3}2GaMe], (3), and [{(C5H5)W(CO)3}3Ga], (4). I.r. evidence suggests that (2) and (3), unlike [{(C5H5)W(CO)3AlMe2}2], do not have –C–O– bridges. An X-ray study of (4) shows that it crystallises in space group P21/n with a= 13.464(4), b= 17.724(5), c= 11.296(3)A, β= 101.72(2)°, Z= 4 (R 0.078 for 2791 reflections). The co-ordination at gallium is planar, and the three tungsten neighbours are at 2.739(3)A.

The product of the reaction between AgI and tris(trimethylsilyl)methyl-lithium in tetrahydrofuran (thf) has been shown by X-ray diffraction to be the ionic ate complex [Li(thf)4][Ag{C(SiMe3)3}2]; evidence is presented that this and the analogous ate complexes of lithium and copper retain their structures in solution.

The compound [{(η-C5H5)W(CO)3(AlMe3)}2], made from trimethylaluminium or dimethylaluminium hydride and the hydride [(η5-C5H5)W(CO)3H], crystallises in space group C2/c with a= 18.120(4), b= 6.188(2), c= 22.266(5)A, β= 93.29(2)°, and Z= 4. The structure, determined by the heavy-atom method from X-ray diffractometer data (1 175 reflections), was refined by least-squares techniques to R 4.2%. The molecules have slightly puckered twelve-membered rings, in which carbonyl groups [C–O,1.22(2)A] are linked through carbon to tungsten [W–C, 1.851 (14)A] and through oxygen to aluminium [Al–O,1.81(1), Al–C,1.94(2)A;: C–Al–C 123(1)°]. Co-ordination round tungsten is completed by cyclopentadienyl groups (W–C 2.31–2.36 A) and by terminal carbonyl groups [W–C 1.97(2), C–O 1.19(3)A]. Absorptions at ca. 1 550 cm–1 are associated with bridging carbonyl groups. The ring is easily broken by protonic species HX [X = Cl, OH, MeCOCHCOMe (acac)], yielding the hydride [(C5H5)W(CO)3H] and the compounds (Me2AlX)n, and by donors D (D = NMe3 or OEt2) giving complexes [(C5H5)W(CO)3(AlMe2)],D. The compounds [{(C5H5)WL(CO)2(AlMe2)}m](L = PPh3, PMe2Ph, or PEt2Ph) were made from trimothylaluminium and the hydrides [(C5H5)WL(CO)2H] : spectroscopic data suggest bridging carbonyl groups in the compounds where L = PMe2Ph or PEt2Ph, similar to those where L = CO. The reaction between dimethylaluminium hydride and pentacarbonylhydridorhenium gives the known hydride [Re3-(CO)14H].

The compound [Me3Al[graphic omitted]IMe2](1), made from the reaction between trimethylaluminium and nitric oxide, crystallises in the triclinic system, with a= 670.6(1), b= 970.3(2), c= 1 020.9(1) pm, α= 82.37 (1), β= 87.13(1)γ= 72.97 (1)°, space group P, and Z= 2. The structure analysis (diffractometer data, 1 214 reflections, R= 0.092) shows that the ONNMeO ligand forms a five-membered chelate ring and that the trimethylaluminium is co-ordinated to the oxygen atom of the nitroso-group. Principal mean molecular parameters are : AL–C 195.3(11), Al–O 189.5(6), N–O 132.2(8), N–N 125.3(9) pm. The position of maximum basicity in the ring at the nitrosyl oxygen is confirmed by ab initio calculations. N.m.r. studies suggest that, in the presence of bases, the complex (1) rearranges to compounds [AlMe(ONNMeO)2](3) and [Al(ONNMeO)3](4) in which the co-ordination number of aluminium is five or six, respectively. The adduct [GaMe2(ONNMeO)](5) has been obtained from trimethylgallium and nitric oxide.

A crystal structure determination on the tetrahydrofuran adduct of tris(trimethylsilyl)methyl-lithium has shown it to be an ate complex, [Li(thf)4][Li{C(SiMe3)3}2].

The organolithium reagent derived from (MeOMe2Si)3CCI has been shown to crystallize as the dimeric species [{LiC(SiMe2OMe)3}2], in which the Li–C bonds are exceptionally long and the C–SiMe2OMe bonds unusually short.

Treatment of Li[C(SiMe3)3] with PPh2Cl gave the phosphine P[C(SiMe3)3]Ph2, which, in spite of the steric crowding caused by the silicon ligand, was readily converted into the phosphonium salts [P{C(SiMe3)3}Ph2H]I and [P{C(SiMe3)3}Ph2Me]I; the latter on heating gave the ylid MePh2PC(SiMe3)2. In methanol at room temperature the phosphine P[C(SiMe3)3]Ph2 readily loses one Me3Si group to give P[CH(SiMe3)2]Ph2; the remaining Me3Si groups are lost successively, with decreasing ease, giving finally PPh2Me. These Si–C bond cleavages are catalysed by acid but inhibited by base, and it is suggested that the initial step is protonation of the phosphine. The quaternary salt [P{C(SiMe3)3}Ph2Me]I successively loses its Me3Si groups very readily in methanol, ultimately to give [PPh2Me2]I.

The lithium–magnesium complex [Li(thf)2(µ-Br)2Mg{C(SiMe3)3}thf](thf = tetrahydrofuran) decomposes of heating in vacuum to give [Mg{C(SiMe3)3}2], which is monomeric; this is the first characterisation of a two-co-ordinate magnesium compound in the solid state.

To the Editor.— We have investigated a case of cholera in Atlanta that apparently resulted from eating raw oysters harvested from the Gulf of Mexico. Previous outbreaks of cholera in the United States have been associated with eating improperly cooked crabs and shrimp, 1 but because oysters are frequently eaten raw they represent a potentially important new vehicle of infection. Oysters are distributed widely and physicians should be alert to the possibility that cholera may occur in inland areas. Report of a Case.— On Nov 8, 1986, a healthy 28-year-old woman with no recent history of travel developed vomiting, abdominal cramps, and profuse watery diarrhea with 40 to 50 loose bowel movements per day. Toxicogenic Vibrio cholerae 01, the organism that causes cholera, was isolated from her stool. She recovered after outpatient therapy with oral rehydration and tetracycline. On Nov 5, she had eaten two dozen raw oysters at a local