A video method for quantifying size distribution, density, and three-dimensional spatial structure of reef fish spawning aggregations

There is a clear need to develop fisheries independent methods to quantify individual sizes, density, and three dimensional characteristics of reef fish spawning aggregations for use in population assessments and to provide critical baseline data on reproductive life history of exploited populations. We designed, constructed, calibrated, and applied an underwater stereo-video system to estimate individual sizes and three dimensional (3D) positions of Nassau grouper (Epinephelus striatus) at a spawning aggregation site located on a reef promontory on the western edge of Little Cayman Island, Cayman Islands, BWI, on 23 January 2003. The system consists of two free-running camcorders mounted on a meter-long bar and supported by a SCUBA diver. Paired video “stills” were captured, and nose and tail of individual fish observed in the field of view of both cameras were digitized using image analysis software. Conversion of these two dimensional screen coordinates to 3D coordinates was achieved through a matrix inversion algorithm and calibration data. Our estimate of mean total length (58.5 cm, n = 29) was in close agreement with estimated lengths from a hydroacoustic survey and from direct measures of fish size using visual census techniques. We discovered a possible bias in length measures using the video method, most likely arising from some fish orientations that were not perpendicular with respect to the optical axis of the camera system. We observed 40 individuals occupying a volume of 33.3 m3, resulting in a concentration of 1.2 individuals m–3 with a mean (SD) nearest neighbor distance of 70.0 (29.7) cm. We promote the use of roving diver stereo-videography as a method to assess the size distribution, density, and 3D spatial structure of fish spawning aggregations

Nassau grouper (Epinephelus striatus) spawning aggregations: hydroacoustic surveys and geostatistical analysis

With the near extinction of many spawning aggregations of large grouper and snapper throughout the Caribbean, Gulf of Mexico, and tropical Atlantic, we need to provide baselines for their conservation. Thus, there is a critical need to develop techniques for rapidly assessing the remaining known (and unknown) aggregations. To this end we used mobile hydroacoustic surveys to estimate the density, spatial extent, and total abundance of a Nassau grouper spawning aggregation at Little Cayman Island, Cayman Islands, BWI. Hydroacoustic estimates of abundance, density, and spatial extent were similar on two sampling occasions. The location and approximate spatial extent of the Nassau grouper spawning aggregation near the shelf-break was corroborated by diver visual observations. Hydroacoustic density estimates were, overall, three-times higher than the average density observed by divers; however, we note that in some instances diver-estimated densities in localized areas were similar to hydroacoustic density estimates. The resolution of the hydroacoustic transects and geostatistical interpolation may have resulted in over-estimates in fish abundance, but still provided reasonable estimates of total spatial extent of the aggregation. Limitations in bottom time for scuba and visibility resulted in poor coverage of the entire Nassau grouper aggregation and low estimates of abundance when compared to hydroacoustic estimates. Although the majority of fish in the aggregation were well off bottom, fish that were sometimes in close proximity to the seafloor were not detected by the hydroacoustic survey. We conclude that diver observations of fish spawning aggregations are critical to interpretations of hydroacoustic surveys, and that hydroacoustic surveys provide a more accurate estimate of overall fish abundance and spatial extent than diver observations. Thus, hydroacoustics is an emerging technology that, when coupled with diver observations, provides a comprehensive survey method for monitoring spawning aggregations of fish

Dihydropyran Ring Conformations. I. Structures of 2-Methoxy- and 2-Hydroxy-2, 4-dimethyl-3, 4-dihydro-2\u3ci\u3eH\u3c/i\u3e, 5\u3ci\u3eH\u3c/i\u3e-Pyrano[3,2-\u3ci\u3ec\u3c/i\u3e][1]benzopyran-5-ones

Conformations of embedded 3,4-dihydro-2H-pyrans (DHP\u27s) are studied in a closely related series of nine molecular structures, including the cis and trans isomers of both racemic and resolved homologs of 2,4-dimethyl-3,4-dihydro-2H,5H-pyrano[3,2-c][l]-benzopyran-5-one. DHP rings in these structures display a range of conformations near the half-chair form but distorted variously toward each of the two inequivalent d,e- and e,f-diplanar forms. Factor analysis reveals the coordination of torsional motions associated with a principal ring-bending mode based on the various ring conformations. Two methyl ketals and an hemiketal structure are reported. (I): (2S,4S)-cis-2-methoxy, C15H16O4, Mr = 260·30, trigonal, P3221, a = 9·579 (5), c = 24·938 (15) Å (hexagonal axes), V = 1981·7 (33) Å, Z = 6, Dx = 1·309 g cm-3, λ(Mo Kᾱ)= 0·71073 Å, μ = 0·884 cm- 1, F(000) = 828, T = 295 K, R = 0·040 for 1470 observations. (II): (2R,4S)-trans-2-methoxy, C15H16O4, Mr = 260·30, monoclinic, P21, a = 9·254 (4), b = 11·970 (5), c = 12·736 (5) Å, β = 105·64 (4)°, V = 1358·5 (22) Å3, Z = 4 (two molecules per asymmetric unit), Dx = 1·274 g cm-3, λ(Mo Kᾱ) = 0·71073 Å, μ = 0·860 cm-1, F(000) = 552, T = 295 K, R = 0·043 for 2923 observations. (III): (2S,4S)-cis-2-hydroxy, C14H14O4, Mr = 246·27, orthorhombic, P212121, a = 6·816 (3), b = 12·826 (7), c = 13·949 (6) Å, V = 1219·4 (17) Å3 , Z = 4, Dx = 1·340 g cm-3, λ(Mo Kᾱ) = 0·71073 Å, μ= 0·919 cm-1, F(000) = 520, T = 293 K, R = 0·046 for 1291 observations

Structure of (Phenyl)bis( 4-hydroxybenzo-2\u3ci\u3eH\u3c/i\u3e-pyran-2-one-3-yl)methane*

A derivative of dicoumarol, C25H16O6, Mr, = 412·41, orthorhombic, P212121, a = 7·959(2), b = 12·865 (3), c = 18·606 (6) Å, V = 1905·3 (22) Å3, Z = 4, Dx = 1.44 g cm-3, λ(Mo Kα) = 0·71073 Å , μ = 0·965 cm-1, F(000) = 856, T = 293 K, final R = 0·042 for 2031 observations. The 4-hydroxycoumarins are intramolecularly hydrogen bonded between hydroxyls and carbonyls, O···O separations are 2·624 (3) and 2·718 (3)Å, a scheme which imparts a dis-symmetry to the otherwise achiral molecule and underlies packing in a polar space group

Religiosity and Sexual Risk Behaviors Among Latina Adolescents: Trends from 1995 to 2008

Purpose: The purpose of this study was to determine trends in the influence of religiosity on sexual activity of Latina adolescents in the United States from 1995 to 2008 and to determine if differences existed between the Mexican American and other Latina groups. Methods: The sample comprised the subset of unmarried, 15–21-year-old (mean 17 years) Latina female respondents in the 1995 (n=267), 2002 (n=306), and 2006–2008 (n=400) National Survey of Family Growth (NSFG) datasets. Associations between religiosity (importance of religion and service attendance) and history of ever having sex, number of sex partners, and age of sexual debut were investigated. Results: Less than one half of Latinas in 1995 (44%) and in 2006–2008 (44%) reported that religion was very important to them, whereas in 2002, 50% reported it was important. Only in 1995 did Latinas who viewed religion as very important have a significantly lower level of sexual initiation. In 1995 and in 2006–2008, Latinas who held religion as very important had significantly fewer partners. In all three cohorts, the higher religious importance group had higher virgin survival rates. Across cohorts, approximately one third of respondents reported frequent religious attendance. In all cohorts, frequent attenders were less likely to have had sex, had fewer partners, and had older age at sexual debut. The survival rate as virgins for Mexican origin Latinas was higher in 1995 and 2002 compared to non-Mexican Latinas but was almost the same in 2006–2008. Conclusions: Religiosity had a protective association with sexual activity among Latina adolescents. The association of importance of religion with sexual activity has diminished from 1995 to 2008, however, whereas the importance of service attendance has remained stable. The influence of religion was more apparent among the Latinas of Mexican origin, but this greater influence also diminished by 2006–2008

α-L-Glutamylglycine

C7H12N 2O5, orthorhombic, P212121, a = 5·525(5), b = 12·565(4), c = 13·211(6) Å, Z = 4, Dc = l·48, Dm (flotation in chloroform/ methylene chloride) = 1·48(1) Mg m-3, R1 = 0·039, R2 = 0·040 for 1172 observations. The dipeptide crystallizes as a zwitterion with the main-chain carboxyl ionized and the amino terminus protonated. The conformation of the peptide group is trans; the glutamyl side chain is extended, but the carboxy terminus is held by hydrogen bonding in a non-extended conformation with a torsional angle ΦGly = -74.1°

α-L-Aspartylglycine Monohydrate

C6H10N2O5, H2O, orthorhombic, P212121, a = 4·844 (5), b = 9·916 (3), c = 18·070(4) Å, V = 868·05 Å3, Z = 4, Dc = 1·59, Dm (flotation in chloroform/iodoform) = l·60 (1) Mg m-3; R1 = 0·040, R2 = 0·033 for 1088 observations. The dipeptide crystallizes as a zwitterion with the main-chain carboxyl ionized and the side-chain amino group protonated. The overall dipeptide conformation is highly extended and the molecule is extensively hydrogen bonded

Structures of Four \u3ci\u3etrans\u3c/i\u3e-2-Hydroxy- and Methoxy-2-methyl-3,4-dihydro-4-alkyl-2\u3ci\u3eH\u3c/i\u3e,5\u3ci\u3eH\u3c/i\u3e-pyrano[3,2-c][1]benzopyran-5-ones

Derivatives of 2-methyl-3,4-dihydro-2H,5H-pyrano[ 3,2-c][1]benzopyran-5-one. ( l) Racemic trans- 2-methoxy-4-(2-propyl), Mr= 288·3, monoclinic, P2i/c, a = 13·737 (3), b = 13·228 (6), c = 17·229(4) Å, β = l02·93(2)° , V = 3051·4 Å3, Z = 8 (two molecules/asymmetric unit), Dx = 1·255 g cm- 3, λ(Mo Kα) = O·71073 Å, μ = 0·908 cm-1 , F(OOO) = 1232, T = 298 K, final R = 0·050 for 3988 unique intensities. Dihydropyran rings in C17H2004 are halfchairs, one being distorted toward the d,e-diplanar form. (2) Resolved trans-2-methoxy-4-cyclohexyl, Mr = 328-4, orthorhombic, P212121, a = 10·468 (5), b = 11·245 (5). c = 14·465 (4) Å, V= 1702·7 Å3, Z=4, Dx= 1·281 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·823 cm- 1 , F(OOO) = 704, T = 298 K, final R = 0·051 for 2481 unique intensities. Compound, C20H2404, spontaneously resolves on crystallization from methanol: acetone; data specimen determined to be 2R,4R by circular dichroism spectrum and comparison with structures of known configuration. Dihydropyran ring has a d,e-diplanar conformation. (3) Racemic trans- 2-hydroxy-4-(2-propyl). Compound crystallizes as the hemihydrate C16H1804. ½H20; Mr= 283-3, triclinic, P1, a = 9·015 (4), b = 10·216 (4), c = 16·208 (5) Å, α = 103·08 (3), β = 95·42 (3), γ = 95·28 (3)° , V = 1437·6 Å3, Z = 4 (two molecules/asymmetric unit), Dx = 1·309 g cm-3 , λ(Mo Kα) = O·71073 Å, μ = 0·890 cm-1, F(OOO) = 604, T = 298 K, final R = 0·040 for 4656 unique reflections. One dihydropyran ring is a half-chair, the other has an ef-diplanar conformation. Intermolecular hydrogen bonding occurs between the water and the hydroxyls and lactone carbonyls of each coumarin with O···O distances between 2·82 and 2·90 Å. (4) Racemic trans-2-hydroxyl-4-(2-propyl) derivative also cocrystallizes with 4-hydroxy-2H-benzopyran- 2-one (1:1), Mr = 436·4, triclinic, P1, a= 8·669 (2), b = 10·506 (4), c = 12.559 (2) Å, α = 102·98 (2), β = 107·56 (2), γ = 93·63 (2)°, V = 1052·0 Å3, Z=2, Dx= 1·378g cm-3, γ(Mo Kα) = 0·71073 Å, μ = 0·941 cm-1, F(OOO) = 460, T = 298 K, final R = 0·041 for 3322 unique reflections. Cocrystalline C16H1804C9H603 shows chains of H bonds linking the hydroxyls of the coumarins alternately with the lactone carbonyls, O···O distances 2·68 and 2·75 Å. The dihydropyran ring has a half-chair conformation

Structures of Five \u3cem\u3etrans\u3c/em\u3e-2-Hydroxy and \u3cem\u3etrans\u3c/em\u3e-2-Methoxy-2-methyl-3,4-dihydro-4-aryl- 2\u3cem\u3eH\u3c/em\u3e,5\u3cem\u3eH\u3c/em\u3e-pyrano[3,2-\u3cem\u3ec\u3c/em\u3e]benzopyran-5-ones

Derivatives of 2-methyl-3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-5-one. (1) Racemic trans-methoxy-4-phenyl, Mr = 322·4, monoclinic, P21/n, a = 5·858 (1), b = 16· 732 (9), c = 16·383 (9) Å, β = 94·82 (3)°, V = 1600·1 Å3, Z = 4, Dx = 1·338 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·866 cm-1, F(000) = 680, T = 298 K, final R = 0·047 for 1513 intensities. The trans methyl ketal of warfarin (C20H18O4) contains a half-chair dihydropyran ring distorted toward the d,e-diplanar conformation. (2) Resolved (2R,4R)-trans-2-methoxy-4-phenyl, Mr = 322·4, orthorhombic, P212121, a = 11·521(1), b = 14·061 (2), c = 10·055(2) Å, V = 1628·9 Å3 , Z = 4, Dx= 1·314 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·851 cm-1, F(000) = 680, T = 298 K, final R = 0·056 for 1660 intensities. The trans methyl ketal (C20H18O4) from R(+)-warfarin; its dihydropyran ring is a half- chair distorted toward the d,e-diplanar conformation. (3) Resolved trans-2-hydroxy-4-(4-methoxyphenyl), Mr = 338·4, orthorhombic, P212121, a = 10·584 (1), b = 10·621(5), c = 14·778 (2) Å, V = 1661·2 Å3, Z = 4, Dx = 1·353 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·908 cm-1, F(000) = 712, T = 298 K, final R = 0·044 for 1165 unique intensities. Compound C20H18O5 spontaneously resolves on crystallization from acetone and water, and absolute configuration of data specimen was not determined. It has a dihydropyran ring with a half-chair conformation; hydroxyl and lactone carbonyl are intermolecularly H-bonded at O···O = 2·79 Å. (4) Racemic trans-2-hydroxy-4-(2-methyl-6-methoxyphenyl), Mr = 372·4, monoclinic, P21/n, a = 9·637 (2), b = 14·345 (4), c = 13·224 (2) Å, β = 91·09 (1)°, V = 1827·8 Å3, Z = 4, Dx = 1·353 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·961 cm-1, F(000) = 784, T = 298 K, final R= 0·048 for 2339 unique intensities. A synthetic derivative of warfarin, it crystallizes as the hydrate C20H18O6.H2O and has a dihydropyran ring with a half-chair conformation and intermolecular H bonds with O···O distances between 2·67 and 2·77 Å. (5) Racemic trans-2-hydroxy-4-(4-dimethylaminophenyl), Mr = 369·4, triclinic, PĪ, a = 9·066 (3), b = 9·509 (2)°, c = 12·681 (3) Å, α = 98·50 (2), β = 91·25 (3), γ = 116·96 (2)°, V = 958·8 Å3, Z = 2, Dx = 1·279 g cm-3, λ(Mo Kα) = 0·71073 Å, μ = 0·854 cm-1, F(000) = 392, T = 298 K, final R = 0·045 on 2773 unique intensities. A synthetic derivative of warfarin, it also crystallizes as a hydrate, C21H21NO4.H2O, and has a dihydropyran ring with a half-chair conformation and intermolecular H bonds with O···O distances between 2·70 and 3·07 Å

Structural Variations in 3,4-Dihydro-2\u3ci\u3eH\u3c/i\u3e-pyran Ketals: Acyl and Aryl Warfarin Derivatives

The crystal structures of ( ± )-cis-2-methyl-5-oxo-4- phenyl-3,4-dihydro-2H,5H-pyrano[3,2-c][1]benzopyran-2-yl acetate [C21H18O5, Mr = 350·37, monoclinic, P21/n, a = 12·091 (4), b = 8·288 (3), c = 17·840 (5) Å, β = 106·34 (2)°, V = l715(2) Å3, Z = 4, Dx = 1·356 g cm-3, λ(Mo Kᾱ) = 0·7107 Å, μ = 0·904 cm-1, F(000) = 736, T = 295 K, R = 0·050 for 2767 observations with I ≥ 3σ(I)] and (6R,12S)-( — )-6,8-dimethyl-6, 12-methano-6H,l2H,l3H-[1] benzopyran[4,3-d][1,3]benzodioxocin-13-one [C20H16O4, Mr = 320·36, tetragonal, P43, a = 10·788 (4), c = 13·587 (9) Å, V = 1581 (2) Å3 , Z = 4, Dx = 1·345 g cm-3, λ(Mo Kᾱ) = 0·7107 Å, μ = 0·873 cm-1, F(000) = 672, T = 295 K, R = 0·049 for 1425 observations with I ≥ 2·5σ(I)] are described. They are acyl and aryl ketals of warfarin, respectively, and contain an embedded dihydropyran ring. The molecules were studied as part of a series of axial 2-O-substituted-2-methyl-3,4-dihydro-2H-pyran structures which show (hemi)ketal C—O bond-length variations indentified through factor analysis with the systematic geometrical changes associated with a spontaneous elimination (El-like) reaction from the ketal leading to 2-methyl-4H-pyran. As in α-tetrahydropyranyl acetals the C—0 lengths in dihydropyranyl ketals can be expressed as a function of the electron-withdrawing ability of the substituent conjugate base, and the slopes of the relat1onsh1ps for the two systems are similar. Corresponding endocyclic C—0 lengths are about 0·052 Å longer in these model dihydropyranyl ketals