South American Data Research Articles

IMPACTO DE LA ANCESTRÍA GENÉTICA EN LA DISTRIBUCIÓN DEL POLIMORFISMO DE INTERFERÓN-λ4 RS12979860 EN UNA POBLACIÓN GLOBAL DE BUENOS AIRES, ARGENTINA

Human interferon-λ4 is a cytokine involved in early stages of antiviral responses. Strikingly, some allelic variants with diminished antiviral activity reduce the susceptibility to viral infections, thus they would have suffered a positive selection pressure throughout the evolutionary history of the genus Homo. An intronic variant within the IFNλ4 locus (rs12979860, T˃C) emerged as one of the main gene determinants of the response to HCV and other viruses. The rs12979860-C allele has a differential frequency in African, European and Native American populations, though South American data are scarce. Here we characterize for the first time the distribution of rs12979860 genotypes in a sample of the global population of Buenos Aires, Argentina, assessing its association with European, Native American and African parental components. The rs12979860 genotypes were determined by PCR-RFLP in DNA samples from donors of a blood banks of Buenos Aires (n=96), whose genetic individual ancestry (European, African or Native American) had been previously determined using molecular markers. The distribution of rs12979860-CC, CT and TT was 29.17%, 50.0% and 20.83%, respectively. A significant increase in the frequency of CC among donors with a strong European contribution and a greater impact of the Native American component among donors carrying the T allele were observed. Native American and European components were associated to the rs12979860 distribution in a sample of the global population of Buenos Aires, while no differences were directly attributable to the African ancestry. Considering interferon´s key role in antiviral responses, our results may contribute to both bioanthropological and immunogenetic studies associated with infectious diseases. Key words: ancestry, Buenos Aires, IFNλ4 polymorphism, rs12979860 distribution.

Risk of neutropenia among clozapine users and non-users: results from 5,847 patients

Objective:Clozapine is underprescribed due to neutropenia risk. Blood tests every 3 months in those on continuous treatment for > 1 year who have never had an absolute neutrophil count (ANC) < 2,000/µL has been proposed as a monitoring strategy; however, there are no South American data to support this recommendation. This study sought to investigate whether clozapine use and other variables could explain the occurrence of ANC < 1,000/µL in patients with severe mental disorders.Methods:A total of 5,847 subjects were included, 1,038 on clozapine. We performed a Cox regression considering the outcome as ANC < 1,000/µL at any time point. Predictors were sex, age, ethnicity, clozapine use, ANC > 2,000/µL during the first year of blood monitoring, and presence of a severe medical condition.Results:In the Cox regression model, ethnicity (white) (hazard ratio [HR] 0.53; 95%CI 0.29-0.99, p < 0.05) and ANC > 2,000/µL (HR 0.04; 95%CI 0.01-0.10, p < 0.001) were protective factors, while presence of a severe medical condition (HR 69.35; 95%CI 37.45-128.44, p < 0.001) was a risk factor for ANC < 1,000/µL. Other variables were not significant, including clozapine use (HR 1.33; 95%CI 0.74-2.39, p > 0.05).Conclusions:These findings suggest that clozapine does not increase the risk of neutropenia in subjects with ANC > 2,000/µL during the first year of use and in the absence of a severe medical condition. These results could help guide clinical and public-health decisions regarding clozapine blood monitoring guidelines.

Seroprevalence of hepatitis E virus in risk populations and blood donors in a referral hospital in the south of Brazil

The prevalence of anti-hepatitis E virus (HEV) antibodies has a high heterogeneity worldwide. South American data are still scarce. The aim of this study was to evaluate the prevalence of HEV in populations at risk in comparison to blood donors (BD). A cross-sectional study was carried out in adults of different risk populations including crack users (CK), residents in a low income area (LIA), cirrhotic (CIR) and liver transplant patients (LT) compared with BD. The WANTAI HEV ELISA test was used and real-time PCR (in-house for screening and ALTONA as confirmatory test) for HEV RNA screening. A total of 400 participants were included. Anti-HEV IgG was positive in 19.5% of the total sample, reaching the highest rate in the CIR group, 22.5%, followed by CK, LT, and LIA (20%, 18.7%, and 17.5%, respectively). The prevalence found in BD individuals was of 18.7% (p = NS). Anti-HEV IgM was positive in only 1.5% of the sample (6/400). No blood or stools samples were positive for HEV RNA. The seroprevalence reported is among the highest rates ever found in Brazil. Considering the intense diagnostic investigation, data show that HEV circulation is more common that might be expected in our country.

Better constrained selection of the Paleozoic West Gondwana (South America) paleomagnetic poles for the APWP determination

The reliability of an Apparent Polar Wander Path (APWP) obviously depends on the paleomagnetic poles used to determine it. The APWP of Africa and South America are fairly well defined for the 330–260 Ma interval. However, this study pointed out a moderate shift between these two curves, and an incoherency of the South American data, contrary to the African ones, which are homogeneous. A number of South American pole positions were re-evaluated in an effort to better constrain the APWP for the entire continent. Most of discarded poles correspond to sites at the area of the junction of Cordillera with the stable craton. That could have structural implications for the evolution of the western margin of the Gondwana. A new criterion for the evaluation of paleomagnetic poles reliability for APWP is presented. Based on comparison of data from different continents and labeled “coherence” criterion, it is independent from Van der Voo’s ones.

ON SEA LEVEL ALONG THE BRAZILIAN COAST

ABSTRACT . This is Part II of a contribution on Brazilian sea levels – Part I dealt with the seasonal variability. It examines the sea level changes along the Brazilian coast from series with less than 40 years of measurement, against the background of changes in series of all continents and islands around the world, considering data distributed by the Permanent Service for Mean Sea Level (PSMSL). The method of analysis follows the display of the data in a: 1) first plot of relative sea level trends (C), against the length of the series (L) expressed in years and a: 2) second plot showing the relative sea level regression coefficients (C), versus the corresponding correlation values (m). The first plot of all PSMSL data exhibited a cusped like shape of the distribution of (C), having maxima values about 10-20 cm/cty for the longest series (120-137 years), indicating the overall positive value of the global relative sea level trend. Similar first plot, a regional plot of African and South American data adjusted to the same global relative mean level, showed that the Brazilian trends (C), are mostly concentrated in the positive side of the cusped: (ports of Bel´em, Fortaleza. Recife, Canavieiras, Salvador, Ilha Fiscal, Rio de Janeiro, Ubatuba, Cananeia, and Imbituba) which have a mean value within 30 to 40 cm/cty. The second plot, with all set of PSMSL data, was necessary in order to display trend values of non simultaneous series of different continental borders and lengths in the same bin. The plot gave two different linear inclinations for trend values within ± 0.3 cm/y, in the positive and negative sides of the figure. The global ratio obtained for the trends was R = − 1.2, suggesting also, from the linearity of the plot, that the trends and correlation values are statistically dependent variables. The graph produced a different value for global balance of the value C obtained in the first plot. Similar regional second plot of the African Atlantic and South American borders, which include the Brazilian data, also gave rise to two new regression lines with trend C*1 0, with a ratio R = − 2.2, involving bins of m and C values that are also null in the vicinity of zero. This regionally plot confirmed the result of the second plot with PSMSL series that they (C and m), globally, should be dependent statistical variables. These findings, however, do not change the fact that the regional series with trends 0.2 cm/year have correlation values m 0 construidas a partir dos valores das tendencias C das series PSMSL, com inclinacoes dentro da faixa de 0,2 cm/ano na parte positiva e negativa da figura, sugerindo uma nao equivalencia entre essas inclinacoes, em favor de valor global negativo de C* para o Nivel Relativo do Mar. Figura semelhante produzida com as s´eries Africanas e Sul Americanas, que incluiram as series brasileiras, mostrou caracteristica similar, alem de indicar que series com tendencias ± 0,2 cm/ano tem valores de correlacao m < 0,3 qualquer que seja o comprimento da serie. Os resultados interessantes, mas contraditorios, que incluem a dependencia linear global entre correlacao e tendencias das series fornecidas pelo PSMSL, devem ser analisados em continuacao aos presentes estudos, que indicam que o nivel relativo do mar na costa brasileira esta aumentando a razao de 30 a 40 cm/seculo. Palavras-chave: nivel do mar, costa brasileira, series do PSMSL, nivel relativo do mar global, balanco do nivel relativo do mar.

Predation on propagules and seedlings in mature and regenerating mangroves in the coast of Ceará, Brazil

Litterfall consumption and predation on propagules is high in Indo-west-Pacific mangroves and low in Atlantic-east-Pacific ones. However, data for the latter area comes only from Caribbean and subtropical North American mangroves. South American data on litterfall consumption contradicts this view but data on predation on propagules are scarce. We measured predation on Rhizophora mangle, Avicennia schaueriana and Laguncularia racemosa propagules and seedlings and related to densities of large (>1.5 m high) and small (1–1.5 m) plants in mature and regenerating mangroves in Ceara state, Brazil. Predation on propagules was the highest among American mangroves (R. mange, >47%; A. schaueriana, >97%; L. racemosa, >83%), especially in the regenerating area. Predation on seedlings was low (maximum of 14% for R. mangle) and did not hamper growth. The dominance of large R. mangle trees in the mature mangrove is consistent with the lower predation on its propagules but the high proportions of small plants of other species indicate that dominance is achieved by mechanisms other than predation. In the regenerating mangrove, dominance of large and small L. racemosa and A. schaueriana plants is not consistent with the high predation on their propagules. Therefore, predation is not the main determinant of the species composition in this mangrove system.

Geographic provenance of aeolian dust in East Antarctica during Pleistocene glaciations: preliminary results from Talos Dome and comparison with East Antarctic and new Andean ice core data

The strontium and neodymium isotopic signature of aeolian mineral particles archived in polar ice cores provides constraints on the geographic provenance of dust and paleo-atmospheric circulation patterns. Data from different ice cores drilled in the centre of the East Antarctic plateau such as EPICA-Dome C (EDC, 75°06′S; 123°21′E) and Vostok (78°28′S, 106°48′E) suggested a uniform geographic provenance for dust during Pleistocene glacial ages, likely from southern South America (SSA). In this work the existing dust isotopic data from EDC have been integrated with new data from Marine Isotopic Stage (MIS) 14 (about 536 ka before 1950AD) and in parallel some first results are shown for the new TALDICE ice core which was drilled on the edge of the East Antarctic Plateau (Talos Dome, 72°48′S, 159°06′E) on the opposite side with respect to SSA. Interestingly, the isotopic composition of TALDICE glacial dust is remarkably similar to that obtained from glacial dust from sites located in the East Antarctic interior. Overall, the glacial dust isotopic field obtained from six East Antarctic ice cores matches well South American data obtained from target areas. In this respect, it was recently suggested that dust exported long-range from South America originates from Patagonia and from the Puna–Altiplano plateau. To test this hypothesis, we analysed the isotopic composition of dust from an ice core drilled on the Illimani glacier (Bolivia, 16°37′S, 67°46′W; 6350 m a.s.l.) in order to obtain information on the isotopic composition of regional mineral aerosol uplifted from the Altiplano area and likely transported over a long distance. Altogether, ice core and source data strongly suggest that the westerly circulation pattern allowed efficient transfer of dust from South America to the East Antarctic plateau under cold Quaternary climates. Isotopic data support the hypothesis of a possible mixing of dust from Patagonia and from the Puna–Altiplano plateau. Interestingly, high glacial dust inputs to Antarctica are characterized by less radiogenic Nd values, an issue suggesting that enhanced dust production in Patagonia was associated with the activation of a secondary source. Still, Patagonia was the most important supplier for dust to central East Antarctica during Quaternary glaciations.

Clusters of sirenomelia in South America

One hospital in the city of Cali, Colombia, of the ECLAMC (Latin-American Collaborative Study of Congenital Malformations) network, reported the unusual occurrence of four cases of sirenomelia within a 55-day period. An ECLAMC routine for cluster evaluation (RUMOR) was followed that included: calculations of observed/expected ratios, site visits, comparison with comprehensively collected local, South American, and worldwide data, cluster analysis, and search for risk factors. All four Cali sirenomelia cases were born to mothers living in a 2 km(2) area, in neighboring communes, within the municipality of Cali. Considering the total births of the city of Cali as the denominator, and based on ECLAMC baseline birth prevalence rates (per 100,000) for sirenomelia (2.25, 95% CI: 2.66, 3.80), the cluster for this congenital abnormality was unlikely to have occurred by chance (observed/expected ratio = 5.77; 95% CI: 1.57-14.78; p = .002). No consistent common factor was identified, but vicinity to an open landfill as the cause could not be rejected. Another ECLAMC hospital in San Justo, Buenos Aires, Argentina, reported three further cases but these did not seem to constitute a nonrandom cluster. The methodology used to evaluate the two possible clusters of sirenomelia determined that the Cali sirenomelia cluster was unlikely to have occurred by chance whereas the sirenomelia cluster from San Justo seemed to be random.

Population viability analysis of monk parakeets in the United States and examination of alternative management strategies

In the United States, monk parakeets (Myiopsitta monachus) are expanding their geographical distribution, and their overall population size is growing exponentially. Monk parakeets are causing widespread economic damage in the United States by nesting on utility structures, which leads to electrical fi res and power outages. Although few life history data are available for the species from North America, extensive data are available from the species' native range in South America. Incorporating data from South America into the population viability analysis program VORTEX, we simulated population growth in United States monk parakeets to determine whether it is likely that the United States population shows life history patterns similar to those in the native range. The answer was, no. The intrinsic rate of growth (r) of monk parakeets in the United States (r = 0.119 during the period 1976-2003) was almost double the rate of population growth (r = 0.064) for the simulated population. Modifying the South American data to allow for reduced mortality, higher fecundity, or a greater proportion of breeding females resulted in population growth rates similar to those in the United States. We extended the simulations to examine the effectiveness of alternative control measures on the monk parakeet population by using the modifi ed life history data. Simulations revealed that it would be necessary to remove 20% of the adult population or to destroy 50% of the nests each year to reduce the population size of monk parakeets. In practical terms, such massive management efforts are unlikely to be sustainable. Instead, control of monk parakeets will likely require an integrated approach including removal of local problem nests on a case-by-case basis and long-term population reduction through trapping or chemical sterilization.

Extinction of Pleistocene megamammals in South America: The lost evidence

The extinction of the Pleistocene megamammals is one of the oldest unsolved questions of South American natural history. Data from this continent are rarely considered in synthesis papers and books produced in the Northern Hemisphere, and sometimes there is a claim that no adequate data can be found. The main point of this presentation is that there is a wealth of both paleontological and archaeological South American data which may help in the evaluation of the different theories and can be used to interpret the extinction event.

Communicative Dynamics of Police-Civilian Encounters: South African and American Interethnic Data

Research in the American West, China, and Taiwan has shown that officers’ communication accommodative practices (and attributed trust in them) can be more potent predictors of satisfaction with the police than are the sociodemographic characteristics of those judging. With Black and White respondents, this study continues this line of work in Louisiana and South Africa and tests a new model about the relationships among perceived officer accommodation, trust in the police, and reported voluntary compliance from civilians. In addition to an array of differences that emerged between nations and ethnicities, officer accommodativeness indirectly predicted civilian compliance through trust. The hypothesized model was partially supported and culturally-sensitive.

The burden of paediatric intensive care: a South American perspective

Paediatric intensive care is a relatively new medical specialty that has shown a marked growing up around the world over the last three decades. The limits and the development of this new specialty are not uniform from country to country. Original articles relating to paediatric intensive care and some South American data bases of health care were evaluated and relevant results were selected. Using these data, we describe the main characteristics of paediatric intensive care in South America and discuss some associated factors (e.g. economic aspects, health systems, ethical aspects) that could interfere with the quality and extent of care. A strong relationship between the financial stability of each region and the complexity and quality of paediatric intensive care was seen. A better coverage and more sophisticated paediatric intensive care units (PICUs) are concentrated in the more developed countries (Brazil, Chile and Argentina). Compared to the northern hemisphere, children admitted to the South American PICUs have higher mortality and higher rates of intervention (mechanical ventilation and indwelling catheters). Medical paternalism has a strong influence in the decision-making process offered to terminally ill patients. This phenomenon increases the length of stay, reduces the number of available beds and increases costs. In conclusion, during the last 20 years PICUs have developed and increased their coverage in South America. However, the most sophisticated and well equipped PICUs are preferentially located in the more developed areas whereas those areas with higher infant mortality rates have few PICU beds. Improvements in the economical stability, regional health organisation as well as the rationale for PICU localisation are some of the important goals to be reached in the near future.

Community-acquired Pneumonia: New Facets of an Old Disease?Hantavirus Pulmonary Syndrome

It seems that with climatic and geoecologic changes, Hantaviruses have re-emerged as human pathogens related to increases in interaction between humans and rodent reservoirs. Infection with SNV in North America and the Andes virus in South America can produce infection manifest initially as a flu-like illness. In the setting of a history of possible exposure to rodents or their excreta, clinical symptoms and laboratory clues such as thrombocytopenia should raise the suspicion of HPS. Clinical deterioration can be rapid, so patients should be hospitalized and transported to tertiary care centers where mechanical ventilation is available if necessary. Presumptive treatment for other forms of sepsis should be considered before confirmation of diagnosis. Survival seems to be determined in part by viral and host factors. Canadian and South American data suggest that there may be species variations influencing clinical manifestations and course of disease. Because the pathogenesis seems to be based on immunologic injury, future treatments will likely focus on interventions other than antiviral medications. Prevention strategies should be emphasized, particularly when recognized climatic conditions favor rodent abundance. Physicians should remain alert to the possibility of such a diagnosis when evaluating a patient with CAP and should request appropriate serology while supporting the patient in a closely monitored setting. The declining mortality rates seen over the past decade may be a consequence of improved medical management or better recognition of cases, including those less severe than originally described.

Archaeomagnetic intensity results from California and Ecuador: evaluation of regional data

We present new archaeointensity data for southeastern California (∼33°N, ∼115°W, 50–1500 yr BP) and northwestern South America (Ecuador, 2.4°S, 80.7°W, 4000–5000 yr BP). These results represent the only data from California, as well as the oldest archaeointensity data now available in northwestern South America. In comparing our results to previously published data for the southwestern United States and northwestern South America, we note that significant scatter in the existing data makes comparisons and interpretations difficult. We undertake an analysis of the sources of data scatter (including age uncertainty, experimental errors, cooling rate differences, magnetic anisotropy, and field distortion) and evaluate the effects of scatter and error on the smoothed archaeointensity record. By making corrections where possible and eliminating questionable data, scatter is significantly reduced, especially in South America, but is far from eliminated. However, we believe the long-period fluctuations in intensity can be resolved, and differences between the Southwestern and South American records can be identified. The Southwest data are distinguished from the South American data by much higher virtual axial dipole moment values from ∼0–600 yr BP and by a broad low between ∼1000–1500 yr BP. Comparisons to global paleofield models reveal disagreements between the models and the archaeointensity data in these two regions, underscoring the need for additional intensity data to constrain the models in much of the world.

Gradients of life-history variation: an intercontinental comparison of fishes

Multivariate analysis identified atwo-dimensional continuum of life-historyvariation among 301 fish species from Europe,North America, South America and the Atlanticand Pacific coasts of North America. The firstaxis was associated with larger body size,higher fecundity, delayed maturation, fewerreproductive events, and shorter breedingseason on one end and small size, lowfecundity, early maturity, multiplereproductive events per year, and prolongedbreeding season on the other. The second axiscontrasted fishes having larger eggs and moreparental care against fishes with the oppositesuite of traits.Phylogenetic affiliations of species wereapparent in the general patterns of ordinationof species within orders, indicatingevolutionary divergences in life-historypatterns. In fact, partitioning the variance oflife-history traits showed that taxonomic orderand latitude were the most important factorsand geographic region and habitat the least.Despite phylogenetic constraints, basiclife-history patterns showed consistencybetween distantly geographical regions,latitudinal ranges and basic adult habitats,indicating convergences in life-historypatterns. Although the basic life-historypatterns seemed repeatable among distantlyrelated taxa, geographical and latitudinalaffiliations were apparent. Species from SouthAmerica are skewed toward the opportunisticendpoint, whereas North American marine speciesare skewed toward the periodic endpoint of thetrilateral continuum model. Most of the fishspecies from South American data set came fromfluctuating environments, so an opportunisticstrategy of early maturation and continuousspawning permits efficient recolonization ofhabitats over small spatial scales. Incontrast, most species in the North Americanand European data sets came from seasonalhabitats that are nonetheless more hydrologicalstable, so a periodic strategy of delayingmaturation to attain large clutches enhancesadult survivorship during suboptimalenvironmental conditions and recruitment whenearly life stages encounter suitableenvironmental conditions. Similarly,latitudinal affiliations were also observed:opportunistic strategists more common intropical latitudes and periodic strategistsmore common in temperate and Arctic latitudes.

The Origin of State Societies in South America

▪ Abstract The earliest states developed in the central Andean highlands and along the central Pacific coast of western South America. The consensus in the archaeological literature is that state societies first developed in the central Andes in the early part of the first millennium C.E. A minority opinion holds that first-generation states developed as early as the late second millennium B.C.E. in the same area. The Andean region constitutes one of a few areas of first-generation state development in the world. This area therefore represents an important case study for the comparative analysis of state formation. This article outlines the arguments for state formation in South America, presents the evidence, analyzes the underlying assumptions about these arguments, and assesses the South American data in terms of contemporary anthropological theory of state evolution.

Life History ofPhalloceros caudiomaculatus: A Novel Variation on the Theme of Livebearing in the Family Poeciliidae

Abstract We describe the life-history pattern of Phalloceros caudiomaculatus on the basis of wild-caught and preserved fish from four different South American locations and laboratory data on livestock from a fifth location. This species is matrotrophic; the estimated dry weight of the young at birth is up to five times the weight of eggs at fertilization. In addition, these fish lack superfetation, meaning that there is only one brood of developing young at a time. This observation suggests that matrotrophy and superfetation can evolve independently of one another. The size distribution of mature males was bimodal in two of three samples and significantly skewed in the third. Such size distributions have indicated the presence of a genetic polymorphism for age and size at maturity in other species of Poeciliidae.

Indigenous South Americans of the past and present: an ecological perspective

Utilizing ethnographic and archaeological data and an updated paradigm derived from the best features of cultural ecology and ecological anthropology, this extensively illustrated book addresses over fifteen South American adaptive systems representing a broad cross section of band, village, chiefdom, and state societies throughout the continent over the past 13,000 years.Indigenous South Americans of the Past and Present presents data on both prehistoric and recent indigenous groups across the entire continent within an explicit theoretical framework. Introductory chapters provide a brief overview of the variability that has characterized these groups over the long period of indigenous adaptation to the continent and examine the historical background of the ecological and cultural evolutionary paradigm. The book then presents a detailed overview of the principal environmental contexts within which indigenous adaptive systems have survived and evolved over thousands of years. It discusses the relationship between environmental types and subsistence productivity, on the one hand, and between these two variables and sociopolitical complexity, on the other. Subsequent chapters proceed in sequential order that is at once evolutionary (from the least to the most complex groups) and geographical (from the least to the most productive environments)?around the continent in counterclockwise fashion from the hunter-gatherers of Tierra del Fuego in the far south; to the villagers of the Amazonian lowlands; to the chiefdoms of the Amazon vÂ?ea and the far northern Andes; and, finally, to the chiefdoms and states of the Peruvian Andes. Along the way, detailed presentations and critiques are made of a number of theories based on the South American data that have worldwide implications for our understanding of prehistoric and recent adaptive systems.

The Sustainability of Political Democracy

Recent literature emphasizes the fragility of newly emerging democracies and the importance of economic performance to their survival. The analysis reevaluates this conventional wisdom and tests a theoretical alternative that takes into account the differential strengths and weaknesses of democracy and authoritarianism as well as institutional variations among democratic regimes. South American data for the post-1944 period form the empirical basis for the study.

Paleomagnetism of the Sassamansville diabase, Newark Basin, southeastern Pennsylvania: Support for Middle Jurassic high-latitude paleopoles for North America

A paleomagnetic study of the Sassamansville diabase, which intrudes the Passaic Formation red beds of the Newark Basin in southeastern Pennsylvania, was conducted to constrain the age of the diabase9s magnetization. Nine sites were collected from the diabase around the Sassamansville syncline. A tenth site was collected at an associated dike 12 km to the north. Eight to ten individually oriented cores were drilled at each site. Alternating field (af) and thermal demagnetization isolated a stable, internally consistent characteristic remanence at eight sites. Using the bedding tilt of the nearest baked or unbaked Passaic Formation sedimentary rocks for a fold test, the site means showed best clustering at 65% unfolding. This magnetization is a statistically significant (at 93% confidence) synfolding magnetization. The diabase9s magnetization fails a baked contact test conducted at one of the sites, indicating that the magnetization is secondary and not a primary thermal remanent magnetization (TRM). Isothermal remanent magnetization (IRM) and partial anhysteretic remanent magnetization (pARM) acquisition experiments and of demagnetization results indicate that the magnetization is carried by high-coercivity magnetite. Anisotropy of magnetic susceptibility (AMS) and anhysteretic remanence (AAR) results indicate that this magnetite has a different fabric from the northeast-southwest horizontally lineated fabric carried by low-coercivity magnetite grains that do not carry the remanence. The lineated fabric may have been caused by flow of the diabase from the north-east to the southwest during emplacement. When the rock magnetic results are considered in light of previous petrographic observations (Davidson and Wyllie, 1968) of these rocks, the rock magnetics suggest that the magnetization is carried by secondary magnetite, which has grown as rims on primary magnetite. The secondary magnetite may have formed during a hydrothermal event proposed by Sutter (1988) based on geochronologic evidence and dated at 175 Ma. If the diabase magnetization is considered to be coeval to a widespread remagnetization (B component) of the Newark Basin sedimentary rocks (Witte and Kent, 1991), the diabase magnetization indicates 15° of counter-clockwise rotation for the Sassamansville syncline. This is consistent with either left-lateral motion along the border fault or along the intrabasinal Chalfont Fault. The presence of counterclockwise block rotations along the border fault could weaken previously reported evidence that the Newark Basin (B component) remagnetization occurred after the Newark Basin strata had acquired most of their north-westerly tilt (Witte and Kent, 1991). Correc-tion for the tilt would move the Newark (B component) remagnetization paleopole to lower paleolatitudes but necessitate significant post-175 Matectonic activity in the Newark Basin. This would contradict the long sedimentary record of rifting and border fault activity for the preceding 50 m.y. A partial tilt correction may be the best geologic and paleomagnetic interpretation because it would minimize the amount of post-175 Ma tectonic activity required while bringing the Newark (B component) remagnetization paleopole into paleolatitudinal agreement with a paleopole derived from the rotation of European, South American, and African data into North American coordinates (Van der Voo, 1992).