Pathologies in satisfaction classes

We study subsets of countable recursively saturated models of $\mathsf{PA}$ which can be defined using pathologies in satisfaction classes. More precisely, we characterize those subsets $X$ such that there is a satisfaction class $S$ where $S$ behaves correctly on an idempotent disjunction of length $c$ if and only if $c \in X$. We generalize this result to characterize several types of pathologies including double negations, blocks of extraneous quantifiers, and binary disjunctions and conjunctions. We find a surprising relationship between the cuts which can be defined in this way and arithmetic saturation: namely, a countable nonstandard model is arithmetically saturated if and only if every cut can be the "idempotent disjunctively correct cut" in some satisfaction class. We describe the relationship between types of pathologies and the closure properties of the cuts defined by these pathologies

Interstructure Lattices and Types of Peano Arithmetic

The collection of elementary substructures of a model of PA forms a lattice, and is referred to as the substructure lattice of the model. In this thesis, we study substructure and interstructure lattices of models of PA. We apply techniques used in studying these lattices to other problems in the model theory of PA. In Chapter 2, we study a problem that had its origin in Simpson, who used arithmetic forcing to show that every countable model of PA has an expansion to PA∗ that is pointwise definable. Enayat later showed that there are 2ℵ0 models with the property that every expansion to PA∗ is pointwise definable. In this Chapter, we use techniques involved in representations of lattices to show that there is a model of PA with this property which contains an infinite descending chain of elementary cuts. In Chapter 3, we study the question of when subsets can be coded in elementary end extensions with prescribed interstructure lattices. This problem originated in Gaifman, who showed that every model of PA has a conservative, minimal elementary end extension. That is, every model of PA has a minimal elementary end extension which codes only definable sets. Kossak and Paris showed that if a model is countable and a subset X can be coded in any elementary end extension, then it can be coded in a minimal extension. Schmerl extended this work by considering which collections of sets can be the sets coded in a minimal elementary end extension. In this Chapter, we extend this work to other lattices. We study two questions: given a countable model M, which sets can be coded in an elementary end extension such that the interstructure lattice is some prescribed finite distributive lattice; and, given an arbitrary model M, which sets can be coded in an elementary end extension whose interstructure lattice is a finite Boolean algebra

Aislación de α-spinasterol de ramas de Amaranthus spinosus

a-Spinasterol fue identificado en ramas de Amaranthus spinosus. La estructura fue obtenida por metodos espectroscópicos y por comparación con datos de literature

Gender-related differences in outcomes and attrition on antiretroviral treatment among an HIV-infected patient cohort in Zimbabwe: 2007-2010.

OBJECTIVES: To determine (1) gender-related differences in antiretroviral therapy (ART) outcomes, and (2) gender-specific characteristics associated with attrition. METHODS: This was a retrospective patient record review of 3919 HIV-infected patients aged ≥15 years who initiated ART between 2007 and 2009 in 40 randomly selected ART facilities countrywide. RESULTS: Compared to females, males had more documented active tuberculosis (12% vs. 9%; p60kg), initiating ART at an urban health facility, and care at central/provincial or district/mission hospitals vs. primary healthcare facilities. CONCLUSIONS: Our findings show that males presented late for ART initiation compared to females. Similar to other studies, males had higher patient attrition and mortality compared to females and this may be attributed in part to late presentation for HIV treatment and care. These observations highlight the need to encourage early HIV testing and enrolment into HIV treatment and care, and eventually patient retention on ART, particularly amongst men

PHYTOCHEMICAL STUDIES OF THE PETROLEUM ETHER EXTRACT OF THE LEAVES OF Lagerstroemia speciosa Linn

Two new compounds, normal alcohol containing of higher carbons and isomer of β-sitosterol were isolated for the first time from the petroleum extract of the leaves of Lagerstroemia speciosa. The structure of the compound has been established on the basis of UV, IR, 1H-NMR, 13C-NMR and mass spectra and identified as nonanol and isomer of β-sitosterol.   Keywords: Lagerstroemia speciosa, petroleum ether extracts, isolation, 1-nonanol, 2 β-sitostero, spectral analyses

A comparative clinical study of bioceramic and calcium hydroxide based root canal sealer in the treatment of non-vital permanent tooth with periapical lesion

Introduction: The use of Bioceramic sealer in the obduration of the root canal system has been expected by many of the previous studies. However, the clinical outcome has not yet been established. Objective: To compare the effectiveness of bioceramic and calcium hydroxide based root canal sealer in treatment of non-vital permanent teeth with periapical lesion (Periapical periodontitis). Materials and Methods: A total 100 mature permanent anterior teeth were selected after clinical and radiological examination which had non-vital pulp with periapical lesion. Clinically pulp vitality test, palpation and percussion test was performed maintaining standard procedure. Following cavity preparation and biomechanical preparation, each canal was obturated either with bioceramic (Endosequence BC) or calcium hydroxide based sealer (Sealapex, Kerr). All participants were evaluated immediately after obturation, at 3 and 6 months for the assessment of change in size of periapical lesion, condition of periodontal ligament space, lamina dura and incidence of post-operative pain, swelling. Statistical analysis was performed using Chi- square(X2) test and t-test. A value of p<0.05 was considered as statistically significant. Results: Bioceramic was more effective in reducing the lesion size than that of calcium hydroxide. At 6 months, the mean lesion size was reduced from 3.52±0.7 to 1.30±0.462 mm in Bioceramics and from 3.48±1.07 to 1.58± 0.498 mm in sealapex treated teeth.. Furthermore, 98% of bioceramic treated teeth and 94% of sealapex treated teeth showed absence of swelling. The differences between two groups were statistically significant (p<0.05). Conclusion: In this short period of study, Bioceramics based sealer seems to be more effective than calcium hydroxide based sealer in repair of periapical lesions of the nonvital teeth

Respondent-Driven Sampling in a Study of Drug Users in New York City: Notes from the Field

Beth Israel Medical Center (BIMC), in collaboration with the Centers for Disease Control (CDC) and the New York State Department of Health (NYSDOH), used respondent-driven sampling (RDS) in a study of HIV seroprevalence among drug users in New York City in 2004. We report here on operational issues with RDS including recruitment, coupon distribution, storefront operations, police and community relations, and the overall lessons we learned. Project staff recruited eight seeds from a syringe exchange in Lower Manhattan to serve as the initial study participants. Upon completion of the interview that lasted approximately 1 h and a blood draw, each seed was given three coupons to recruit three drug users into the study. Each of the subsequent eligible participants was also given three coupons to recruit three of their drug-using acquaintances. Eligible participants had to have: injected, smoked or snorted an illicit drug in the last 6 months (other than marijuana), aged 18 or older, adequate English language knowledge to permit informed consent and complete questionnaire. From April to July 2004, 618 drug users were interviewed, including 263 (43%) current injectors, 119 (19%) former injectors, and 236 (38%) never injectors. Four hundred sixty nine (76%) participants were men, 147 (24%) were women, and two (<1%) were transgender. By race/ethnicity, 285 (46%) were black, 218 (35%) Hispanic, 88 (14%) white, 23 (4%) mixed/not specified, and four (<1%) native American. Interviews were initially done on a drop-in basis but this system changed to appointments 1 month into the study due to the large volume of subjects coming in for interviews. Data collection was originally proposed to last for 1 year with a target recruitment of 500 drug users. Utilizing RDS, we were able to recruit and interview 118 more drug users than originally proposed in one quarter of the time. RDS was efficient with respect to time and economics (we did not have to hire an outreach worker) and effective in recruiting a diverse sample of drug users

Respondent-driven sampling bias induced by community structure and response rates in social networks

Sampling hidden populations is particularly challenging by using standard sampling methods mainly because of the lack of a sampling frame. Respondent‐driven sampling is an alternative methodology that exploits the social contacts between peers to reach and weight individuals in these hard‐to‐reach populations. It is a snowball sampling procedure where the weight of the respondents is adjusted for the likelihood of being sampled due to differences in the number of contacts. The structure of the social contacts thus regulates the process by constraining the sampling within subregions of the network. We study the bias induced by network communities, which are groups of individuals more connected between themselves than with individuals in other groups, in the respondent‐driven sampling estimator. We simulate different structures and response rates to reproduce real settings. We find that the prevalence of the estimated variable is associated with the size of the network community to which the individual belongs and observe that low degree nodes may be undersampled if the sample and the network are of similar size. We also find that respondent‐driven sampling estimators perform well if response rates are relatively large and the community structure is weak, whereas low response rates typically generate strong biases irrespectively of the community structure