An olivine cumulate outcrop on the floor of Jezero crater, Mars.

The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigated the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We found that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multistage cooling of a thick magma body.

A cross-sectional analysis of psychological distress among higher education students in Ireland.

OBJECTIVES: To examine levels of psychological distress among higher education students in Ireland overall and across a range of personal, higher education, and socioeconomic characteristics, prior to the COVID-19 pandemic. METHODS: A cross-sectional online survey of college students in Ireland was undertaken in 2018. Data on 5201 students from 13 higher education institutions (HEIs) were analyzed. Stress, anxiety, and depression symptom scores based on the Depression, Anxiety and Stress Scale (DASS-21) were calculated and reported, with statistical testing used to compare across groups. RESULTS: Overall, 29.6% and 19.1% of respondents were classified in the mild to moderate and severe to extremely severe range for depression respectively. The corresponding proportions were 25.9% and 20.7% for anxiety, and 24.5% and 14.8% for stress. Differences across groups included higher levels of psychological distress for transgender and female students compared to males (p < 0.01), for gay/lesbian/bisexual students compared to heterosexuals (p < 0.01), for undergraduates compared to postgraduates (p < 0.01), for students from intermediate/technical/service/unskilled social classes compared to professional/self-employed social classes (p < 0.01), and for those with financial difficulties compared to those without financial difficulties (p < 0.01). CONCLUSIONS: Rates of psychological distress were high amongst college students in Ireland prior to the COVID-19 pandemic, with substantial differences across groups. Due to study limitations, such as possible selection bias, the findings need replication. Further research is needed to determine the impact of the pandemic on the prevalence of mental illness in this population.

Characteristics, Origins, and Biosignature Preservation Potential of Carbonate-Bearing Rocks Within and Outside of Jezero Crater.

Carbonate minerals have been detected in Jezero crater, an ancient lake basin that is the landing site of the Mars 2020 Perseverance rover, and within the regional olivine-bearing (ROB) unit in the Nili Fossae region surrounding this crater. It has been suggested that some carbonates in the margin fractured unit, a rock unit within Jezero crater, formed in a fluviolacustrine environment, which would be conducive to preservation of biosignatures from paleolake-inhabiting lifeforms. Here, we show that carbonate-bearing rocks within and outside of Jezero crater have the same range of visible-to-near-infrared carbonate absorption strengths, carbonate absorption band positions, thermal inertias, and morphologies. Thicknesses of exposed carbonate-bearing rock cross-sections in Jezero crater are ∼75-90 m thicker than typical ROB unit cross-sections in the Nili Fossae region, but have similar thicknesses to ROB unit exposures in Libya Montes. These similarities in carbonate properties within and outside of Jezero crater is consistent with a shared origin for all of the carbonates in the Nili Fossae region. Carbonate absorption minima positions indicate that both Mg- and more Fe-rich carbonates are present in the Nili Fossae region, consistent with the expected products of olivine carbonation. These estimated carbonate chemistries are similar to those in martian meteorites and the Comanche carbonates investigated by the Spirit rover in Columbia Hills. Our results indicate that hydrothermal alteration is the most likely formation mechanism for non-deltaic carbonates within and outside of Jezero crater.

Hydrocarbons preserved in a ~2.7 Ga outcrop sample from the Fortescue Group, Pilbara Craton, Western Australia.

The hydrocarbons preserved in an Archean rock were extracted, and their composition and distribution in consecutive slices from the outside to the inside of the rock were examined. The 2.7 Ga rock was collected from the Fortescue Group in the Pilbara region, Western Australia. The bitumen I (solvent-extracted rock) and bitumen II (solvent-extracted hydrochloric acid-treated rock) fractions have different hydrocarbon compositions. Bitumen I contains only trace amounts of aliphatic hydrocarbons and virtually no aromatic hydrocarbons. In contrast, bitumen II contains abundant aliphatic and aromatic hydrocarbons. The difference seems to reflect the weathering history and preservational environment of the investigated rock. Aliphatic hydrocarbons in bitumen I are considered to be mainly from later hydrocarbon inputs, after initial deposition and burial, and are therefore not indigenous. The lack of aromatic hydrocarbons in bitumen I suggests a severe weathering environment since uplift and exposure of the rock at the Earth's surface in the Cenozoic. On the other hand, the high abundance of aromatic hydrocarbons in bitumen II suggests that bitumen II hydrocarbons have been physically isolated from removal by their encapsulation within carbonate minerals. The richness of aromatic hydrocarbons and the relative scarcity of aliphatic hydrocarbons may reflect the original compositions of organic materials biosynthesised in ancient organisms in the Archean era, or the high thermal maturity of the rock. Cyanobacterial biomarkers were observed in the surficial slices of the rock, which may indicate that endolithic cyanobacteria inhabited the surface outcrop. The distribution of aliphatic and aromatic hydrocarbons implies a high thermal maturity, which is consistent with the lack of any specific biomarkers, such as hopanes and steranes, and the prehnite-pumpellyite facies metamorphic grade.

Long-term clinical response to cardiac resynchronisation therapy under a multidisciplinary model.

BACKGROUND: Cardiac resynchronisation therapy (CRT) is established in the management of cardiac failure in patients with systolic dysfunction. Clinical response to CRT is not uniform, and response has been difficult to predict. AIM: Patient management within a high volume, multidisciplinary service focused on optimal delivery of CRT would improve response rates. METHODS: Four hundred and thirty-five consecutive patients who underwent CRT under a multidisciplinary heart failure service were enrolled prospectively over a 5-year period. Medically optimised, symptomatic patients with an ejection fraction (EF) <35%, widened QRS or abnormal dyssynchrony index were included. Left ventricular lead position was targeted anatomically to the segment of latest mechanical activation, and electrically to a site with maximal intrinsic intracardiac electrogram separation. Routine device and clinical follow up, as well as CRT optimisations, were performed at baseline and at 3-monthly intervals. Responders were defined as having an absolute reduction in left ventricular end-diastolic diameter >10% and an improvement in EF >5%. RESULTS: With a mean follow up of 53 ± 11 months, response rate to CRT was 81%. Mean EF improved from 26 ± 10% to 37 ± 11%, and mean left ventricular end-diastolic diameter reduced from 68.6 ± 9.2 mm to 57.8 ± 9.3 mm. Predictors of response were sinus rhythm, high dyssynchrony index and intrinsic electrical dyssynchrony >80 ms. Successful LV lead implantation at initial procedure was achieved in 99.1%, and at latest follow up 94.6% of initial LV leads were still active. CONCLUSION: CRT undertaken with a unit focus on optimal LV lead positioning and device optimisation, along with a multidisciplinary follow-up model, results in an excellent response rate to CRT.

HIV disclosure among adults living with HIV.

Research on disclosure among heterosexual adult person(s) living with HIV (PLH) was reviewed, omitting disclosure of parental HIV to children. Disclosure has been studied within five additional relational contexts: with partners, family members, friends, healthcare professionals and in work settings. Disclosure is higher among women than men, among Latino and white compared to African-American families, and among younger compared to older HIV-positive adults. Most PLH disclose to their sexual partners and family members, yet there is a significant minority who do not disclose. Similarly, rates of disclosure to employers range from 27-68%, suggesting broad variability in perceived consequences of employment disclosures. Of concern, 40% of PLH do not consistently disclose to their healthcare professionals. Rather than examine HIV disclosures in the context of relationships, it is possible to understand disclosures around personal identity. Disclosure decisions are often made to tell everyone (making HIV status a central attribute of one's identity), no one (requiring strategies for securing social support while remaining anonymous) or some people (requiring strategic decisions based on context). Given that disclosure decisions are central to personal identity, future data on disclosure and interventions designed to increase disclosure or comfort with disclosure must focus on communication strategies adopted by PLH to present a coherent identity.

Families living with HIV.

Given the historical emergence of the AIDS epidemic first among gay men in the developed world, HIV interventions have primarily focused on individuals rather than families. Typically not part of traditional family structures, HIV-positive gay men in Europe and the US lived primarily in societies providing essential infrastructure for survival needs that highly value individual justice and freedom. Interventions were thus designed to focus on at-risk individuals with programmes that were age and gender segregated. As the epidemic has unfolded, the early focus on individuals has become inadequate: families live with HIV, not just individuals. Families' structure, economy, migration patterns, and developmental life cycles are affected by HIV, and these changes radiate throughout the community creating parallel stresses. Family-based, intergenerational models of detection, prevention and treatment services offer enhanced opportunities for effective interventions and suggest very different intervention settings and strategies. However, these models also require addressing the family's basic needs for survival and security in order to be successfully implemented and sustained over time. As HIV was an opportunity for marginalized persons in the developed world to 'turn their life around', the strengths of families in the developing world may be mobilized to contribute to the community's long-term health, survival and security needs.

Designing health information delivery systems for Puerto Rican women.

Although health information is important to the prevention of much illness, the health information needs of Puerto Rican women remain unaddressed, according to the results of this phenomenological study. Through audiotaped interviews, 21 women evaluated various sources of health information. Analysis of the data revealed which health information sources they considered trustworthy and nontrustworthy. Health care providers were found to be one of the least helpful sources, as personal interactions were often hurried and inattentive to women's needs. Yet, the women were able to present a vivid portrait of a culturally sensitive community environment conducive to the presentation of health information. Implications include the importance of including cultural values in any health information setting, as well as the importance of building cultural bridges between health educators and Puerto Rican women. More research is needed to examine community efforts to enhance health information sources for this population of women.

Packed red cell transfusion does not compromise chromosome analysis in newborns.

PURPOSE: Critically ill neonates are frequently transfused with packed red cells. Some of these transfused neonates also need chromosome analysis. There is a long-standing tradition in pediatrics of not performing chromosome analysis after transfusion. We wished to determine whether transfusion with packed red cells affect the cytogenetic results in neonates. METHOD: The medical records of all neonates at the Medical College of Georgia who had had chromosome analysis between June 1995 and June 1998 were reviewed. Ten neonates had received transfusion prior to cytogenetic testing. Of these 10 infants, two had been transfused two or more times. Routine cytogenetic analysis of 20 metaphases at 550-band level had been performed on all 10 patients. Heteromorphic markers were compared in 10 randomly selected metaphases for any discrepancy. To determine whether there were theoretical reasons to delay chromosome analysis in transfused neonates, samples of irradiated, and/or filtered, and nonfiltered blood were obtained from the blood bank and analyzed for the presence of lymphocytes. RESULTS: Prior transfusion did not affect karyotype results. A nonmosaic abnormal karyotype was found in 3 of the 10 patients. A fourth patient's karyotype was 45,X/47,XXX. This mosaicism was constitutive and consistent as demonstrated by a follow-up chromosome analysis. All other abnormal karyotypes were consistent with the dysmorphic phenotype. Randomly selected metaphases did not show any differences in the identifiable heteromorphic markers in all 10 patients. Although there was a 50% chance of patients receiving blood from a donor of opposite sex, there were no instances in which cells with a karyotype of the opposite sex were found in the patients' blood. The irradiated and filtered cultured donor blood samples did not show any metaphases. However, metaphases were seen in the cultures from nonfiltered and nonirradiated donor blood. CONCLUSIONS: Based on these results one does not need to delay karyotyping babies who have had blood transfusions. Packed red cell transfusion in newborns does not compromise the accuracy of chromosome analysis in our study even with multiple transfusions.

Violence exposure, psychological trauma, and suicide risk in a community sample of dangerously violent adolescents.

OBJECTIVE: To examine violence exposure, violent behaviors, psychological trauma, and suicide risk in a community sample of dangerously violent adolescents by comparison with a matched community sample of nonviolent adolescents. METHOD: Anonymous self-report questionnaires were administered in the 1992-1993 school year to students in grades 9 through 12, in six public high schools located in Ohio and Colorado (N = 3,735). From this sample, 484 adolescents (349 males, 135 females) who reported attacking someone with a knife or shooting at someone within the past year (i.e., dangerously violent adolescents) were drawn. Four hundred eighty-four controls were also selected and matched on gender, age in years, ethnicity, area of residence, and family structure. RESULTS: Dangerously violent adolescents reported higher levels of exposure to violence and victimization than did matched controls. Dangerously violent females were more likely to score in the clinical range of depression, anxiety, posttraumatic stress, anger, and dissociation than were control females and violent males; they also had significantly higher levels of suicide potential. CONCLUSIONS: Students who have been known to commit violent acts should be adequately assessed for violence exposure and symptoms of psychological trauma, with special attention given to the suicide potential of violent females.

The relationship between children's threats of violence and violent behaviors.

BACKGROUND: We sought to examine the relationship between students' threats of interpersonal violence and self-reported violent behaviors. METHODS: Anonymous self-report questionnaires were administered to students in grades 3 through 12 in schools located in Colorado, Arizona, and Ohio. A survey of 9487 students from 33 public schools was performed. Ages ranged from 7 to 19 years. Across the 3 samples, the percentage of African Americans ranged from 6% to 35%, whites from 31% to 57%, and Hispanics from 5% to 51%. RESULTS: Multivariate logistic regression analyses revealed that threatening others infrequently or frequently (compared with not threatening others) was significantly associated with violent behaviors. Students who infrequently threatened were about 3 to 4 times more likely to report exhibiting each of the violent behaviors than students who did not threaten others (odds ratio [OR] = 4.08-5.86). The relationship between frequently threatening others and violent behaviors was especially strong (OR = 7.19-24.30) and highest for the most severe forms of violence, knife attacks (OR = 15.39-24.30) and shootings (OR = 18.42). CONCLUSIONS: Findings suggest that students' threats of harm toward others should be taken seriously, and that policies and procedures should be developed to ensure that children who threaten others receive proper assessment and management. Arch Pediatr Adolesc Med. 2000;154:785-790

Avian endogenous retrovirus EAV-HP shares regions of identity with avian leukosis virus subgroup J and the avian retrotransposon ART-CH.

The existence of novel endogenous retrovirus elements in the chicken genome, designated EAV-HP, with close sequence identity to the env gene of avian leukosis virus (ALV) subgroup J has been reported (L. M. Smith, A. A. Toye, K. Howes, N. Bumstead, L. N. Payne, and K. Venugopal, J. Gen. Virol. 80:261-268, 1999). To resolve the genome structure of these retroviral elements, we have determined the complete sequence of two proviral clones of EAV-HP from a line N chicken genomic DNA yeast artificial chromosome library and from a meat-type chicken line 21 lambda library. The EAV-HP sequences from the two lines were 98% identical and had a typical provirus structure. The two EAV-HP clones showed identical large deletions spanning part of the gag, the entire pol, and part of the env genes. The env region of the EAV-HP clones was 97% identical to the env sequence of HPRS-103, the prototype subgroup J ALV. The 5' region of EAV-HP comprising the R and U5 regions of the long terminal repeat (LTR), the untranslated leader, and the 5' end of the putative gag region were 97% identical to the avian retrotransposon sequence, ART-CH. The remaining gag sequence shared less than 60% identity with other ALV sequences. The U3 region of the LTR was distinct from those of other retroviruses but contained some of the conserved motifs required for functioning as a promoter. To examine the ability of this endogenous retroviral LTR to function as a transcriptional promoter, the EAV-HP and HPRS-103 LTR U3 regions were compared in a luciferase reporter gene assay. The low luciferase activity detected with the EAV-HP LTR U3 constructs, at levels close to those observed for a control vector lacking the promoter or enhancer elements, suggested that these elements function as a weak promoter, possibly accounting for their low expression levels in chicken embryos.

Subgroup J avian leukosis virus infection in turkeys: induction of rapid onset tumours by acutely transforming virus strain 966.

Avian leukosis virus subgroup J (ALV-J), isolated in the late 1980s, predominantly causes myelocytic myeloid leukosis in meat-type chickens. In the past 10 years, ALV-J infection has become very widespread, causing serious problems to the chicken meat industry. Previously, we have shown that turkey cells can be infected in vitro with Rous sarcoma virus pseudotypes of ALV-J. In this paper, we extend those observations to show that turkey monocyte cultures can be transformed in vitro with acutely transforming ALV-J strain 966. We also show that turkeys are experimentally susceptible to infection with ALV-J prototype strain HPRS-103. However, neoplastic lesions were not observed in these birds, probably due to the short experimental period of 10 weeks. When inoculated into 1-day-old turkey poults, acutely transforming ALV-J strain 966 induced tumours between 3 and 4 weeks after infection. Most of the birds showed tumours involving the liver, with histopathological lesions of myelocytomatosis. The demonstration of the spread of HPRS-103 by contact among turkeys, although observed only at low levels in the present study, stresses the importance of segregation of turkey and chicken breeding operations to avoid the spread of ALV-J infection.

Isolation of acutely transforming subgroup J avian leukosis viruses that induce erythroblastosis and myelocytomatosis.

Avian leukosis virus of subgroup J (ALV-J), isolated in the late 1980s, predominantly causes myelocytic myeloid leukosis in meat-type chickens. In the past few years, we have observed the occurrence of lesions indicative of erythroblastosis in ALV-J-infected flocks and, in this paper, we report the isolation of ALV-J strains from such flocks. Three of these isolates were acutely transforming viruses, as shown by their ability to transform bone marrow cell cultures. The bone marrow cultures transformed by these virus isolates were very similar to the myeloid cells transformed by the ALV-J strain 966. However, the infection of meat-type chickens with these isolates either as embryos or as 1-day-old chicks resulted in the induction of erythroblastosis as well as myelocytomatosis. Other histopathological changes observed in the inoculated birds included neoplastic lesions such as cholangioma and testicular cell tumour, and non-neoplastic lesions such as lymphomyeloid hyperplasia. This report demonstrates that highly oncogenic ALV-J, capable of inducing a different spectrum of disease other than the widely reported myelocytomatosis, could be established in naturally infected flocks.

Isolation of acutely transforming subgroup J avian leukosis viruses that induce erythroblastosis and myelocytomatosis.

Avian leukosis virus of subgroup J (ALV-J), isolated in the late 1980s, predominantly causes myelocytic myeloid leukosis in meat-type chickens. In the past few years, we have observed the occurrence of lesions indicative of erythroblastosis in ALV-J-infected flocks and, in this paper, we report the isolation of ALV-J strains from such flocks. Three of these isolates were acutely transforming viruses, as shown by their ability to transform bone marrow cell cultures. The bone marrow cultures transformed by these virus isolates were very similar to the myeloid cells transformed by the ALV-J strain 966. However, the infection of meat-type chickens with these isolates either as embryos or as 1-day-old chicks resulted in the induction of erythroblastosis as well as myelocytomatosis. Other histopathological changes observed in the inoculated birds included neoplastic lesions such as cholangioma and testicular cell tumour, and non-neoplastic lesions such as lymphomyeloid hyperplasia. This report demonstrates that highly oncogenic ALV-J, capable of inducing a different spectrum of disease other than the widely reported myelocytomatosis, could be established in naturally infected flocks.

Contributors to violent behavior among elementary and middle school children.

OBJECTIVE: To examine the relative contributions of exposure to violence, parental monitoring, and television-viewing habits to children's self-reported violent behaviors. The study hypothesized that: 1) children's exposure to violence would be associated positively with self-reported violent behaviors; 2) parental monitoring would be associated negatively with children's violent behaviors; and 3) the number of daily television-viewing hours and a preference for watching violent television shows would be associated positively with children's violent behaviors. METHODS: The study used a survey design with an anonymous self-report questionnaire administered to students (grades 3-8) in 11 public schools. A total of 2245 students participated in the study, representing 80% of the students attending the participating schools during the survey. The subjects were from 7 to 15 years of age; 51% were male, 57% were white, 33% percent were black, and 5% were Hispanic. RESULTS: Hierarchical multiple regression analysis of the total sample revealed that the combination of demographic variables, parental monitoring, television-viewing habits, and exposure to violence explained 45% of students' self-reported violent behaviors. Violence exposure and parental monitoring were the most influential contributors in explaining children's violent behaviors, accounting for 24% and 5% of the variance in violent behaviors, respectively. CONCLUSIONS: All three hypotheses were supported. A significant association was demonstrated linking violence exposure, lack of parental monitoring, and television-viewing habits with children's self-reported violent behaviors within a diverse sample of elementary and middle school students. Our findings support the importance of parental monitoring of children and emphasize the need to identify and to provide services to youth who are exposed to violence.

Microdeletion of chromosome sub-band 2q37.3 in two patients with abnormal situs viscerum.

We report on two cases of microdeletion of chromosome sub-band 2q37.3 with abnormal situs viscerum. The first patient had dextrocardia, duodenal and jejunal atresia, and an abdominal hernia. The liver was in the left upper quadrant, stomach in the right upper quadrant. In contrast anema the ascending colon was in the left, and descending colon on the right, with an area of atresia in the mid-jejunum. The second patient had malrotation and malposition of large and small bowel, with most of the bowels positioned above the liver and spleen. There was incomplete rotation of the cecum. The right kidney was malrotated and mal-positioned. The finding of 2q37.3 deletion in both patients implies that a locus or loci involved in the development of normal body situs lies within this chromosome region. Molecular cytogenetic evaluation for a possible 2q37.3 deletion should be considered in patients with abnormal situs viscerum.

Who are they with and what are they doing? Delinquent behavior, substance use, and early adolescents' after-school time.

The relationship among after-school time, parental monitoring, and problem behavior was examined in a sample of 1,170 early adolescents. Those spending unsupervised time with peers reported higher levels of aggression, delinquency, substance use, and susceptibility to peer pressure, and lower levels of parental monitoring, than did adolescents at home with parents. Adolescents home alone after school were similar to those who spent time with adults or in school activities.

Fiber-optic chemical sensing with langmuir-blodgett overlay waveguides.

Fiber-optic chemical sensing has been demonstrated with a side-polished single-mode optical fiber, evanescently coupled to chemically sensitive Langmuir-Blodgett (LB) overlay waveguides. The sensors exhibit a channel-dropping response centered on a wavelength that is dependent on the thickness and the refractive index of the overlay waveguide. It has been shown that pH-sensitive organic dyes proved to be suitable materials for the formation of an overlay waveguide whereas LB deposition provides the required thickness control. A theoretical model of the sensor response, based on the Kramers-Kronig relations and phase matching of the guided modes within the optical fiber and overlay waveguide, shows good agreement with experimental results.