Salt marsh ecosystem biogeochemical responses to nutrient enrichment: a paired N-15 tracer study

We compared processing and fate of dissolved NO3- in two New England salt marsh ecosystems, one receiving natural flood tide concentrations of similar to 1-4 mu mol NO3-/L and the other receiving experimentally fertilized flood tides containing similar to 70-100 mu mol NO3-/L. We conducted simultaneous (NO3-)-N-15 (isotope) tracer additions from 23 to 28 July 2005 in the reference (8.4 ha) and fertilized (12.4 ha) systems to compare N dynamics and fate. Two full tidal cycles were intensively studied during the paired tracer additions. Resulting mass balances showed that essentially 100% (0.48-0.61 mol NO3-N.ha(-1).h(-1)) of incoming NO3- was assimilated, dissimilated, sorbed, or sedimented (processed) within a few hours in the reference system when NO3- concentrations were 1.3-1.8 mu mol/L. In contrast, only 50-60% of incoming NO3- was processed in the fertilized system when NO3- concentrations were 84-96 mu mol/ L; the remainder was exported in ebb tidewater. Gross NO3- processing was similar to 40 times higher in the fertilized system at 19.34- 24.67 mol NO3-N.ha(-1).h(-1). Dissimilatory nitrate reduction to ammonium was evident in both systems during the first 48 h of the tracer additions but \u3c1% of incoming (NO3-)-N-15 was exported as (NH4+)-N-15. Nitrification rates calculated by (NO3-)-N-15 dilution were 6.05 and 4.46 mol.ha(-1).h(-1) in the fertilized system but could not be accurately calculated in the reference system due to rapid (\u3c4 h) NO3- turnover. Over the five-day paired tracer addition, sediments sequestered a small fraction of incoming NO3-, although the efficiency of sequestration was 3.8% in the reference system and 0.7% in the fertilized system. Gross sediment N sequestration rates were similar at 13.5 and 12.6 mol.ha(-1).d(-1), respectively. Macrophyte NO3- uptake efficiency, based on tracer incorporation in aboveground tissues, was considerably higher in the reference system (16.8%) than the fertilized system (2.6%), although bulk uptake of NO3- by plants was lower in the reference system (1.75 mol NO3-.ha(-1).d(-1)) than the fertilized system (similar to 10 mol NO3-.ha(-1).d(-1)). Nitrogen processing efficiency decreased with NO3- load in all pools, suggesting that the nutrient processing capacity of the marsh ecosystem was exceeded in the fertilized marsh

Pseudospectral methods for atoms in strong magnetic fields

We present a new pseudospectral algorithm for the calculation of the structure of atoms in strong magnetic fields. We have verified this technique for one, two and three-electron atoms in zero magnetic fields against laboratory results and find typically better than one-percent accuracy. We further verify this technique against the state-of-the-art calculations of hydrogen, helium and lithium in strong magnetic fields (up to about $2\times 10^{6}$ T) and find a similar level of agreement. The key enabling advantages of the algorithm are its simplicity (about 130 lines of commented code) and its speed (about $10^2-10^5$ times faster than finite-element methods to achieve similar accuracy).Comment: 10 pages, version accepted to MNRA

Two novel susceptibility loci for prostate cancer in men of African ancestry

Prostate cancer incidence is 1.6-fold higher in African Americans than in other populations. The risk factors that drive this disparity are unknown and potentially consist of social, environmental, and genetic influences. To investigate the genetic basis of prostate cancer in men of African ancestry, we performed a genome-wide association meta-analysis using two-sided statistical tests in 10 202 case subjects and 10 810 control subjects. We identified novel signals on chromosomes 13q34 and 22q12, with the risk-associated alleles found only in men of African ancestry (13q34: rs75823044, risk allele frequency = 2.2%, odds ratio [OR] = 1.55, 95% confidence interval [CI] = 1.37 to 1.76, P = 6.10 × 10-12; 22q12.1: rs78554043, risk allele frequency = 1.5%, OR = 1.62, 95% CI = 1.39 to 1.89, P = 7.50 × 10-10). At 13q34, the signal is located 5\u27 of the gene IRS2 and 3\u27 of a long noncoding RNA, while at 22q12 the candidate functional allele is a missense variant in the CHEK2 gene. These findings provide further support for the role of ancestry-specific germline variation in contributing to population differences in prostate cancer risk

A germline variant at 8q24 contributes to familial clustering of prostate cancer in men of African ancestry

Although men of African ancestry have a high risk of prostate cancer (PCa), no genes or mutations have been identified that contribute to familial clustering of PCa in this population. We investigated whether the African ancestry-specific PCa risk variant at 8q24, rs72725854, is enriched in men with a PCa family history in 9052 cases, 143 cases from high-risk families, and 8595 controls of African ancestry. We found the risk allele to be significantly associated with earlier age at diagnosis, more aggressive disease, and enriched in men with a PCa family history (32% of high-risk familial cases carried the variant vs 23% of cases without a family history and 12% of controls). For cases with two or more first-degree relatives with PCa who had at least one family member diagnosed at age \u3c60 yr, the odds ratios for TA heterozygotes and TT homozygotes were 3.92 (95% confidence interval [CI] = 2.13-7.22) and 33.41 (95% CI = 10.86-102.84), respectively. Among men with a PCa family history, the absolute risk by age 60 yr reached 21% (95% CI = 17-25%) for TA heterozygotes and 38% (95% CI = 13-65%) for TT homozygotes. We estimate that in men of African ancestry, rs72725854 accounts for 32% of the total familial risk explained by all known PCa risk variants. PATIENT SUMMARY: We found that rs72725854, an African ancestry-specific risk variant, is more common in men with a family history of prostate cancer and in those diagnosed with prostate cancer at younger ages. Men of African ancestry may benefit from the knowledge of their carrier status for this genetic risk variant to guide decisions about prostate cancer screening

Susceptibility of salt marshes to nutrient enrichment and predator removal

Salt marsh ecosystems have been considered not susceptible to nitrogen overloading because early studies suggested that salt marshes adsorbed excess nutrients in plant growth. However, the possible effect of nutrient loading on species composition, and the combined effects of nutrients and altered species composition on structure and function, was largely ignored. Failure to understand interactions between nutrient loading and species composition may lead to severe underestimates of the impacts of stresses. We altered whole salt marsh ecosystems (similar to 60 000 m(2)/treatment) by addition of nutrients in flooding waters and by reduction of a key predatory fish, the mummichog. We added nutrients (N and P; 15-fold increase over ambient conditions) directly to the flooding tide to mimic the way anthropogenic nutrients are delivered to marsh ecosystems. Despite the high concentrations (70 mmol N/L) achieved in the water column, our annual N loadings (15-60 g N.m(-2).yr(-1)) were an order of magnitude less than most plot-level fertilization experiments, yet we detected responses at several trophic levels. Preliminary calculations suggest that 30-40% of the added N was removed by the marsh during each tidal cycle. Creek bank Spartina alterniflora and high marsh S. patens production increased, but not stunted high marsh S. alterniflora. Microbial production increased in the fertilized creek bank S. alterniflora habitat where benthic microalgae also increased. We found top-down control of benthic microalgae by killifish, but only under nutrient addition and in the opposite direction (increase) than that predicted by a fish-invertebrate-microalgae trophic cascade. Surprisingly, infauna declined in abundance during the first season of fertilization and with fish removal. Our results demonstrate ecological effects of both nutrient addition and mummichog reduction at the whole-system level, including evidence for synergistic interactions

The burden of prostate cancer in Trinidad and Tobago: One of the highest mortality rates in the world

PURPOSE: In Trinidad and Tobago (TT), prostate cancer (CaP) is the most commonly diagnosed malignancy and the leading cause of cancer deaths among men. TT currently has one of the highest CaP mortality rates in the world. METHODS: 6,064 incident and 3,704 mortality cases of CaP occurring in TT from January 1995 to 31 December 2009 reported to the Dr. Elizabeth Quamina Cancer population-based cancer registry for TT, were analyzed to examine CaP survival, incidence, and mortality rates and trends by ancestry and geography. RESULTS: The age-standardized CaP incidence and mortality rates (per 100,000) based on the 1960 world-standardized in 2009 were 64.2 and 47.1 per 100,000. The mortality rate in TT increased between 1995 (37.9 per 100,000) and 2009 (79.4 per 100,000), while the rate in the US decreased from 37.3 per 100,000 to 22.1 per 100,000 over the same period. Fewer African ancestry patients received treatment relative to those of Indian and mixed ancestry (45.7%, 60.3%, and 60.9%, respectively). CONCLUSIONS: Notwithstanding the limitations surrounding data quality, our findings highlight the increasing burden of CaP in TT and the need for improved surveillance and standard of care. Our findings highlight the need for optimized models to project cancer rates in developing countries like TT. This study also provides the rationale for targeted screening and optimized treatment for CaP to ameliorate the rates we report

She Broke My Heart in Three Places

Map of United States inside broken hearthttps://scholarsjunction.msstate.edu/cht-sheet-music/12226/thumbnail.jp

Priorities to promote participant engagement in the Participant Engagement and Cancer Genome Sequencing (PE-CGS) Network

BACKGROUND: Engaging diverse populations in cancer genomics research is of critical importance and is a fundamental goal of the NCI Participant Engagement and Cancer Genome Sequencing (PE-CGS) Network. Established as part of the Cancer Moonshot, PE-CGS is a consortium of stakeholders including clinicians, scientists, genetic counselors, and representatives of potential study participants and their communities. Participant engagement is an ongoing, bidirectional, and mutually beneficial interaction between study participants and researchers. PE-CGS sought to set priorities in participant engagement for conducting the network\u27s research. METHODS: PE-CGS deliberatively engaged its stakeholders in the following four-phase process to set the network\u27s research priorities in participant engagement: (i) a brainstorming exercise to elicit potential priorities; (ii) a 2-day virtual meeting to discuss priorities; (iii) recommendations from the PE-CGS External Advisory Panel to refine priorities; and (iv) a virtual meeting to set priorities. RESULTS: Nearly 150 PE-CGS stakeholders engaged in the process. Five priorities were set: (i) tailor education and communication materials for participants throughout the research process; (ii) identify measures of participant engagement; (iii) identify optimal participant engagement strategies; (iv) understand cancer disparities in the context of cancer genomics research; and (v) personalize the return of genomics findings to participants. CONCLUSIONS: PE-CGS is pursuing these priorities to meaningfully engage diverse and underrepresented patients with cancer and posttreatment cancer survivors as participants in cancer genomics research and, subsequently, generate new discoveries. IMPACT: Data from PE-CGS will be shared with the broader scientific community in a manner consistent with participant informed consent and community agreement

Vascular endothelial growth factor receptor 3 signaling contributes to angioobliterative pulmonary hypertension

The mechanisms involved in the development of severe angioobliterative pulmonary arterial hypertension (PAH) are multicellular and complex. Many of the features of human severe PAH, including angioobliteration, lung perivascular inflammation, and right heart failure, are reproduced in the Sugen 5416/chronic hypoxia (SuHx) rat model. Here we address, at first glance, the confusing and paradoxical aspect of the model, namely, that treatment of rats with the antiangiogenic vascular endothelial growth factor (VEGF) receptor 1 and 2 kinase inhibitor, Sugen 5416, when combined with chronic hypoxia, causes angioproliferative pulmonary vascular disease. We postulated that signaling through the unblocked VEGF receptor VEGFR3 (or flt4) could account for some of the pulmonary arteriolar lumen-occluding cell growth. We also considered that Sugen 5416-induced VEGFR1 and VEGFR2 blockade could alter the expression pattern of VEGF isoform proteins. Indeed, in the lungs of SuHx rats we found increased expression of the ligand proteins VEGF-C and VEGF-D as well as enhanced expression of the VEGFR3 protein. In contrast, in the failing right ventricle of SuHx rats there was a profound decrease in the expression of VEGF-B and VEGF-D in addition to the previously described reduction in VEGF-A expression. MAZ51, an inhibitor of VEGFR3 phosphorylation and VEGFR3 signaling, largely prevented the development of angioobliteration in the SuHx model; however, obliterated vessels did not reopen when animals with established PAH were treated with the VEGFR3 inhibitor. Part of the mechanism of vasoobliteration in the SuHx model occurs via VEGFR3. VEGFR1/VEGFR2 inhibition can be initially antiangiogenic by inducing lung vessel endothelial cell apoptosis; however, it can be subsequently angiogenic via VEGF-C and VEGF-D signaling through VEGFR3