(Table 1) Age and depth of reflectors of the 3.5-kHz and airgun seismic record and their corresponding depth of ash layers, carbonate peaks, and transition zones from DSDP Hole 83-504B

DSDP cores from areas of low (Site 505) and high heat flow (Site 504 B) near the Costa Rica Rift, together with seismic profiles from the Panama Basin, have been studied to determine the relationship between: (1) carbonate content and physical and acoustic properties; and (2) carbonate content, carbonate diagenesis and acoustic stratigraphy. Except for ash and chert layers, bulk density correlates strongly and linearly with carbonate content. Velocity is uniform downcore and only small variations at a small scale are measured. Thus an abrupt change in carbonate content will cause abrupt changes in acoustic impedance and should cause reflectors that can be detected acoustically. A comparison of seismic profiler reflection records with physical properties, carbonate content and reflection coefficients indicates that the main reflectors can be identified with ash layers, diagenetic boundaries, and carbonate content variations. Diagenesis of carbonate sediments is present at Site 504B in a 260 m-thick ooze-chalk-limestone/chert sequence. These diagenetic sequences occur in areas of higher heat flow (200 mW/m**2). Seismic profiler records can be used to map the extent and depth of these diagenetic boundaries.

Saginaw river, Michigan. Letter from the Secretary of War, transmitting, with a letter from the chief of engineers, reports on preliminary examination and survey of Saginaw river, Michigan, with a view to securing a depth of twenty feet from Saginaw Bay to Tittabawassee river.

Mode of access: Internet.

Operator's manual : boring machine, engine cylinder, portable, 3 1/2 to 7 1/2 bore diameter, 18 inch depth of bore, 110-volt, 60-cycle, single-phase (Cedar Rapids Engineering Company model FL) (4910-223-9734).

"November 1965."

Depth of cure and surface microhardness of composite resin cured with blue LED curing lights

Objectives. This study examined the depth of cure and surface microhardness of Filtek Z250 composite resin (3M-Espe) (shades B1, A3, and C4) when cured with three commercially available tight emitting diode (LED) curing lights [E-light (GC), Elipar Freelight (3M-ESPE), 475H (RF Lab Systems)], compared with a high intensity quartz tungsten halogen (HQTH) light (Kerr Demetron Optilux 501) and a conventional quartz tungsten halogen (QTH) lamp (Sirona S1 dental unit). Methods. The effects of light source and resin shade were evaluated as independent variables. Depth of cure after 40 s of exposure was determined using the ISO 4049:2000 method, and Vickers hardness determined at 1.0 mm intervals. Results. HQTH and QTH lamps gave the greatest depth of cure. The three LED lights showed similar performances across all parameters, and each unit exceeded the ISO standard for depth of cure except GC ELight for shade B1. In terms of shade, LED lights gave greater curing depths with A3 shade, while QTH and HQTH tights gave greater curing depths with C4 shade. Hardness at the resin surface was not significantly different between LED and conventional curing lights, however, below the surface, hardness reduced more rapidly for the LED lights, especially at depths beyond 3 mm. Significance. Since the performance of the three LED lights meets the ISO standard for depth of cure, these systems appear suitable for routine clinical application for resin curing. (C) 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

A survey of possible associations between preharvest environment conditions and postharvest rejections of cut freesia flowers

Botrytis cinerea is the major pathogen infecting cut freesia flowers. Flecking symptoms on petals caused by this fungus result in postharvest rejections and substantial economic loss to both growers and sellers. In a limited survey for industry, numbers of freesia stems sent from a specialist grower in The Netherlands and rejected at a cut flower wholesaler in the United Kingdom were documented. Relationships between preharvest environment conditions in Holland that may predispose flowers to infection and postharvest freesia rejection levels in the United Kingdom due to B. cinerea flecking symptom expression are reported. Freesia rejections peaked during spring and, to a lesser degree, autumn periods. However, no clear correlations between preharvest growing environment conditions (e.g. 3-day means for temperature preceding harvest) and postharvest rejection frequency (%) could be discerned. Thus, sporadic freesia rejections in the United Kingdom were probably attributable either to other unresolved variables during the pre- (e.g. infection pressure) and/or postharvest (e.g. condensation events) phases or to interactions among predisposing variables.

Effects of vase solution pH and abscisic acid on the longevity of cut 'Baccara' roses

Abscisic acid (ABA) supplied in the vase solution can induce stomatal closure in the leaves of cut flowers, including roses (Rosa hybrida L.). This effect may be beneficial in reducing water deficit stress. Extracellular pH can affect active ABA concentrations in the apoplast of guard cells, with sap alkalisation enhancing the physiological activity of ABA. Accordingly, it was hypothesized that vase solution pH may affect ABA-mediated stomatal closure of cut roses. Two experiments were conducted to study the interaction of vase solution pH and ABA. In the first, cut 'Baccara' roses were held in vase solutions with +/- 10(-5) M ABA at pH 6, pH 7 and pH 8. In the second experiment, roses were held with +/- 10(-5) M ABA at pH 6 and pH 8 in the presence and absence of 1 mg l(-1) AgNO3 as a bactericide. Supply of ABA increased vase life and reduced vase solution usage of flowers held in low pH 6 solutions, indicating induction of stomatal closure. Conversely, ABA supplied at pH 8 was associated with reduced vase life. This negative result was associated with enhanced development of vase solution microbes at high pH, which overrode any potential pH-mediated ABA efficacy effects.

Effect of seasonal variation and storage temperature on leaf chlorophyll fluorescence and vase life of cut roses

Low temperature injury (LTI) of roses (Rosa hybrida L.) is difficult to assess by visual observation. Relative chlorophyll fluorescence (CF; F-v/F-m) is a non-invasive technique that provides an index of stress effects on photosystem 11 (PS 11) activity. This instrumental technique allows determination of the photosynthetic efficiency of plant tissues containing chloroplasts, such as rose leaves. In the present study, pre- and Post-Storage measurements of F-v/F-m were carried out to assess LTI in 'First Red' and 'Akito' roses harvested year round. Relationships between the pre-harvest environment conditions of temperature, relative humidity and photon flux density (PFD), F-v/F-m, and, vase life duration after storage are reported. After harvest, roses were stored at 1, 5 and 10 degrees C for 10 days. Non-stored roses were the control treatment. F-v/F-m ratios were reduced following storage, suggesting LTI of roses. However, reductions in F-v/F-m were not closely correlated with reduced vase life duration and were seasonally dependent. Only during winter experiments was F-v/F-m of roses stored at 1 degrees C significantly (P <= 0.001) lower compared to F-v/F-m of non-stored control roses and roses stored at 5 and 10 degrees C. Thus, the fall of F-v/F-m was due to an interaction of growing season and storage at 1 degrees C. Vase lives of roses grown during winter were significantly (P <= 0.001) shorter compared to roses grown during summer. Length of vase life was intermediate for roses grown during autumn and spring. Because of the lack of correlation between F-v/F-m and post-storage vase life it is concluded that the CF parameter F-v/F-m is nota practical index for assessing LTI in cold-stored roses. Higher PFD and temperature in summer were positively and significantly correlated with maintenance of post-storage FvIF ratios and longer vase life. It is suggested that shorter vase lives and lower post-storage F-v/F-m values after storage at 1 degrees C are consequences of reduced photosynthesis and smaller carbohydrate pools in winter-harvested roses. (c) 2004 Elsevier B.V All rights reserved.