Method and apparatus for phasing segmented mirror arrays

A method and an apparatus are disclosed for edge phasing an array of segments in a segmented primary telescope mirror using white light from a far field source and starting with the inner edge of each segment in the first ring of segments. The segments are individually phased for zero piston and tilt error with respect to the edge of a reference surface in the open center position of the telescope mirror. After edge phasing of all segments in the telescope mirror array is completed, full surface phasing can be achieved by using a conventional Shack-Hartmann technique followed by finding the RMS best fit for each segment of the mirror array

Precision segmented reflector, figure verification sensor

The Precision Segmented Reflector (PSR) program currently under way at the Jet Propulsion Laboratory is a test bed and technology demonstration program designed to develop and study the structural and material technologies required for lightweight, precision segmented reflectors. A Figure Verification Sensor (FVS) which is designed to monitor the active control system of the segments is described, a best fit surface is defined, and an image or wavefront quality of the assembled array of reflecting panels is assesse

SWEPT CONICS: Single Mirror Transformers

A class of optical surfaces called 'Swept Conics' or 'Conical Spheroids' can be used to transform wavefronts from point sources to diffraction limited line or arc images, and vice versa

Point Relay Scanner Utilizing Ellipsoidal Mirrors

A scanning system uses a polygonal mirror assembly with each facet of the polygon having an ellipsoidal mirror located thereon. One focal point of each ellipsoidal mirror is located at a common point on the axis of rotation of the polygonal mirror assembly. As the mirror assembly rotates. a second focal point of the ellipsoidal mirrors traces out a scan line. The scanner can be utilized for scanned output display of information or for scanning information to be detected

Three-year randomised clinical trial to evaluate the clinical performance, quantitative and qualitative wear patterns of hybrid composite restorations

The aim of the study was to compare the clinical performance, quantitative and qualitative wear patterns of conventional hybrid (Tetric Ceram), micro-filled hybrid (Gradia Direct Posterior) and nano-hybrid (Tetric EvoCeram, TEC) posterior composite restorations in a 3-year randomised clinical trial. Sixteen Tetric Ceram, 17 TEC and 16 Gradia Direct Posterior restorations were placed in human molars and evaluated at baseline, 6, 12, 24 and 36 months of clinical service according to US Public Health Service criteria. The gypsum replicas at each recall were used for 3D laser scanning to quantify wear, and the epoxy resin replicas were observed under scanning electron microscope to study the qualitative wear patterns. After 3 years of clinical service, the three hybrid restorative materials performed clinically well in posterior cavities. Within the observation period, the nano-hybrid and micro-hybrid restorations evolved better in polishability with improved surface gloss retention than the conventional hybrid counterpart. The three hybrid composites showed enamel-like vertical wear and cavity-size dependant volume loss magnitude. Qualitatively, while the micro-filled and nano-hybrid composite restorations exhibited signs of fatigue similar to the conventional hybrid composite restorations at heavy occlusal contact area, their light occlusal contact areas showed less surface pitting after 3 years of clinical service

Phylogenetics of Seed Plants: An Analysis of Nucleotide Sequences from the Plastid Gene rbcL

We present the results of two exploratory parsimony analyses of DNA sequences from 475 and 499 species of seed plants, respectively, representing all major taxonomic groups. The data are exclusively from the chloroplast gene rbcL, which codes for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO or RuBPCase). We used two different state-transformation assumptions resulting in two sets of cladograms: (i) equal-weighting for the 499-taxon analysis; and (ii) a procedure that differentially weights transversions over transitions within characters and codon positions among characters for the 475-taxon analysis. The degree of congruence between these results and other molecular, as well as morphological, cladistic studies indicates that rbcL sequence variation contains historical evidence appropriate for phylogenetic analysis at this taxonomic level of sampling. Because the topologies presented are necessarily approximate and cannot be evaluated adequately for internal support, these results should be assessed from the perspective of their predictive value and used to direct future studies, both molecular and morphological. In both analyses, the three genera of Gnetales are placed together as the sister group of the flowering plants, and the anomalous aquatic Ceratophyllum (Ceratophyllaceae) is sister to all other flowering plants. Several major lineages identified correspond well with at least some recent taxonomic schemes for angiosperms, particularly those of Dahlgren and Thorne. The basalmost clades within the angiosperms are orders of the apparently polyphyletic subclass Magnoliidae sensu Cronquist. The most conspicuous feature of the topology is that the major division is not monocot versus dicot, but rather one correlated with general pollen type: uniaperturate versus triaperturate. The Dilleniidae and Hamamelidae are the only subclasses that are grossly polyphyletic; an examination of the latter is presented as an example of the use of these broad analyses to focus more restricted studies. A broadly circumscribed Rosidae is paraphyletic to Asteridae and Dilleniidae. Subclass Caryophyllidae is monophyletic and derived from within Rosidae in the 475-taxon analysis but is sister to a group composed of broadly delineated Asteridae and Rosidae in the 499-taxon study

Partner- and partnership-related risk factors for preterm birth among low-income women in Lima, Peru

A woman's partner and the characteristics of their partnership can play an important role in the health of her pregnancy. Yet, with the notable exception of intimate partner violence, there has been little previous research addressing the associations between partner- or partnership-related factors and birth outcomes. This analysis tested the hypothesis that risk factors related specifically to partner or partnership characteristics increased the risk for preterm birth. Between 2003 and 2005, a total of 580 preterm cases (20-36 weeks gestational age at delivery) and 633 term controls (>=37 weeks) were selected from women delivering at an obstetric hospital in Lima, Peru. Each woman completed a confidential, structured interview and provided biological specimens within 48 h after delivery. Multivariable logistic regression was used to assess associations between partner and partnership characteristics and preterm birth. After adjustment for behavioral, demographic, and obstetric risk factors, ever having had a partner with a history of drug use (aOR = 1.91, 95% CI 1.22-2.99), ever having had anal sex (aOR = 1.40, 95% CI 1.07-1.84), having a current partner with a history of visiting prostitutes (aOR = 1.69, 95% CI 1.22-2.33), and perceiving one's current partner as a "womanizer" (aOR = 1.34, 95% CI 1.02-1.77) were significantly associated with an elevated risk of preterm birth when tested in separate models. These four factors were then used to create a composite partnership risk score, which showed an increasing dose-response relationship with preterm birth risk (per additional partner risk factor: aOR = 1.31, 95% CI 1.16-1.49). These results highlight the importance of considering a broader set of risk factors for preterm birth, specifically those related to a woman's partner and partnership characteristics. Further research could clarify the specific mechanisms through which these partner and partnership characteristics may increase the risk of preterm birth.Peru Preterm birth Risk Sexually transmitted infections Partner and partnership factors Women

Reasons for receiving or not receiving HPV vaccination in primary schoolgirls in Tanzania: a case control study.

BACKGROUND: There are few data on factors influencing human papillomavirus (HPV) vaccination uptake in sub-Saharan Africa. We examined the characteristics of receivers and non-receivers of HPV vaccination in Tanzania and identified reasons for not receiving the vaccine. METHODS: We conducted a case control study of HPV vaccine receivers and non-receivers within a phase IV cluster-randomised trial of HPV vaccination in 134 primary schools in Tanzania. Girls who failed to receive vaccine (pupil cases) and their parents/guardians (adult cases) and girls who received dose 1 (pupil controls) of the quadrivalent vaccine (Gardasil™) and their parents/guardians (adult controls) were enrolled from 39 schools in a 1∶1 ratio and interviewed about cervical cancer, HPV vaccine knowledge and reasons why they might have received or not received the vaccine. Conditional logistic regression was used to determine factors independently associated with not receiving HPV vaccine. RESULTS: We interviewed 159 pupil/adult cases and 245 pupil/adult controls. Adult-factors independently associated with a daughter being a case were older age, owning fewer household items, not attending a school meeting about HPV vaccine, and not knowing anyone with cancer. Pupil-factors for being a case included having a non-positive opinion about the school de-worming programme, poor knowledge about the location of the cervix, and not knowing that a vaccine could prevent cervical cancer. Reasons for actively refusing vaccination included concerns about side effects and infertility. Most adult and pupil cases reported that they would accept the HPV vaccine if it were offered again (97% and 93% respectively). CONCLUSIONS: Sensitisation messages, especially targeted at older and poorer parents, knowledge retention and parent meetings are critical for vaccine acceptance in Tanzania. Vaccine side effects and fertility concerns should be addressed prior to a national vaccination program. Parents and pupils who initially decline vaccination should be given an opportunity to reconsider their decision

In vitro evaluation of marginal and internal adaptation of class II CAD/CAM ceramic restorations with different resinous bases and interface treatments

This in vitro study evaluated the influence of different composite bases and surface treatments on marginal and internal adaptation of class II CEREC CAD/CAM ceramic inlays, before and after simulated occlusal loading