Evaluating two soil carbon models within the global land surface model JSBACH using surface and spaceborne observations of atmospheric CO₂

The trajectories of soil carbon (C) in the changing climate are of utmost importance, as soil carbon is a substantial carbon storage with a large potential to impact the atmospheric carbon dioxide (CO2) burden. Atmospheric CO2 observations integrate all processes affecting C exchange between the surface and the atmosphere. Therefore they provide a benchmark for carbon cycle models. We evaluated two distinct soil carbon models (CBALANCE and YASSO) that were implemented to a global land surface model (JSBACH) against atmospheric CO2 observations. We transported the biospheric carbon fluxes obtained by JSBACH using the atmospheric transport model TM5 to obtain atmospheric CO2. We then compared these results with surface observations from Global Atmosphere Watch (GAW) stations as well as with column XCO2 retrievals from the GOSAT satellite. The seasonal cycles of atmospheric CO2 estimated by the two different soil models differed. The estimates from the CBALANCE soil model were more in line with the surface observations at low latitudes (0 N–45 N) with only 1 % bias in the seasonal cycle amplitude (SCA), whereas YASSO was underestimating the SCA in this region by 32 %. YASSO gave more realistic seasonal cycle amplitudes of CO2 at northern boreal sites (north of 45 N) with underestimation of 15 % compared to 30 % overestimation by CBALANCE. Generally, the estimates from CBALANCE were more successful in capturing the seasonal patterns and seasonal cycle amplitudes of atmospheric CO2 even though it overestimated soil carbon stocks by 225 % (compared to underestimation of 36 % by YASSO) and its predictions of the global distribution of soil carbon stocks was unrealistic. The reasons for these differences in the results are related to the different environmental drivers and their functional dependencies of these two soil carbon models. In the tropical region the YASSO model showed earlier increase in season of the heterotophic respiration since it is driven by precipitation instead of soil moisture as CBALANCE. In the temperate and boreal region the role of temperature is more dominant. There the heterotophic respiration from the YASSO model had larger annual variability, driven by air temperature, compared to the CBALANCE which is driven by soil temperature. The results underline the importance of using sub-yearly data in the development of soil carbon models when they are used in shorter than annual time scales

Liver transplantation for alcoholic cirrhosis: Long term follow-up and impact of disease recurrence

Background. Alcoholic liver disease has emerged as a leading indication for hepatic transplantation, although it is a controversial use of resources. We aimed to examine all aspects of liver transplantation associated with alcohol abuse. Methods. Retrospective cohort analysis of 123 alcoholic patients with a median of 7 years follow-up at one center. Results. In addition to alcohol, 43 (35%) patients had another possible factor contributing to cirrhosis. Actuarial patient and graft survival rates were, respectively, 84% and 81% (1 year); 72% and 66% (5 years); and 63% and 59% (7 years). After transplantation, 18 patients (15%) manifested 21 noncutaneous de novo malignancies, which is significantly more than controls (P=0.0001); upper aerodigestive squamous carcinomas were over-represented (P=0.03). Thirteen patients had definitely relapsed and three others were suspected to have relapsed. Relapse was predicted by daily ethanol consumption (P=0.0314), but not by duration of pretransplant sobriety or explant histology. No patient had alcoholic hepatitis after transplantation and neither late onset acute nor chronic rejection was significantly increased. Multiple regression analyses for predictors of graft failure identified major biliary/vascular complications (P=0.01), chronic bile duct injury on biopsy (P=0.002), and pericellular fibrosis on biopsy (P=0.05); graft viral hepatitis was marginally significant (P=0.07) on univariate analysis. Conclusions. Alcoholic liver disease is an excellent indication for liver transplantation in those without coexistent conditions. Recurrent alcoholic liver disease alone is not an important cause of graft pathology or failure. Potential recipients should be heavily screened before transplantation for coexistent conditions (e.g., hepatitis C, metabolic diseases) and other target-organ damage, especially aerodigestive malignancy, which are greater causes of morbidity and mortality than is recurrent alcohol liver disease

Genital Tract Sequestration of SIV following Acute Infection

We characterized the evolution of simian immunodeficiency virus (SIV) in the male genital tract by examining blood- and semen-associated virus from experimentally and sham vaccinated rhesus monkeys during primary infection. At the time of peak virus replication, SIV sequences were intermixed between the blood and semen supporting a scenario of high-level virus "spillover" into the male genital tract. However, at the time of virus set point, compartmentalization was apparent in 4 of 7 evaluated monkeys, likely as a consequence of restricted virus gene flow between anatomic compartments after the resolution of primary viremia. These findings suggest that SIV replication in the male genital tract evolves to compartmentalization after peak viremia resolves

Safety and Toxicity of Catheter Gene Delivery to the Pulmonary Vasculature in a Patient with Metastatic Melanoma

Overview summary Transcatheter delivery of HLA-B7 DNA and cationic liposomes into a segment of a pulmonary artery was safely performed in 1 patient with tumor nodules in the lung. No immunologic or organ toxicities were observed. Percutaneous catheter gene delivery has been performed in humans. Further refinements of this approach may lead to useful treatments for a variety of human diseases.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63196/1/hum.1994.5.9-1089.pd

Estudio paleomagnético de las manifestaciones tipo pórfido cuprífero de Farallón negro, Provincia de Catamarca

El objetivo del presente trabajo fue obtener informaciónrespecto a la génesis de los yacimientos de cobre diseminado presentes en Farallón Negro, sobre la base del estudio paleomagnéticode los mismos. Con ese fin se estudiaron muestras provenientes de cincobajos topográficos conocidos como: Bajo del Durazno, Bajo del Agua Tapada, Bajo Las Pampitas, Bajo La Alumbrera y Bajo San Lucas,donde se ha verificado la existencia de los mencionados yacimientos. También se estudiaron paleomagnéticamente muestras derocas sin alterar del Grupo Volcánico Farallón Negro que pudieranestar vincuiadas genéticamente con la mineralización. Las direcciones de la magnetización remanente estable provenientes de las rocas mineralizadas se alinearon a lo largo dedos círculos máximos sugiriendo la presencia de fenómenos de remagnetizacióne indicando que las rocas debieron haber adquiridodurante su historia geológica más de una remanencia. Para que la información obtenida resulte comparable conlos circulos de confianza de las direcciones medias, se han trazado bandas de direcciones con un ancho equivalente a dos desviacionesstandard, las que se utilizan por primera vez con este fin (en conocimiento de la autora) en la bibliografía paleomagnética. La intersección de dichas bandas ha permitido definir unárea dentro del cual se encuentra la dirección de magnetizaciónestable representativa del fenómeno hidrotermal. La comparación de dicha información con aquella proveniente de las rocas sin alterar del Grupo Volcánico Farallón Negro sugiere que las monzonitas y las riodacitas son las rocas que pudieron estar vinculadas genéticamente con la mineralización. Estees un aporte del presente estudio, el que demuestra la validezdel método para dilucidar vinculaciones genéticas en yacimientoshidrotermales de cobre diseminado. A su vez se ha sugerido la posibilidad de que el fenómeno hidrotermalse produjera con anterioridad al ascenso delas Sierras Pampeanas circundantes y se ha discutido las relacionesentre la mineralización y el sistema de fracturas presentesdentro del área de YMAD.Fil: Nabel, Paulina E.. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Reconstituted B cell receptor signaling reveals carbohydrate-dependent mode of activation

Activation of immune cells (but not B cells) with lectins is widely known. We used the structurally defined interaction between influenza hemagglutinin (HA) and its cell surface receptor sialic acid (SA) to identify a B cell receptor (BCR) activation modality that proceeded through non-cognate interactions with antigen. Using a new approach to reconstitute antigen-receptor interactions in a human reporter B cell line, we found that sequence-defined BCRs from the human germline repertoire could be triggered by both complementarity to influenza HA and a separate mode of signaling that relied on multivalent ligation of BCR sialyl-oligosaccharide. The latter suggested a new mechanism for priming naïve B cell responses and manifested as the induction of SA-dependent pan-activation by peripheral blood B cells. BCR crosslinking in the absence of complementarity is a superantigen effect induced by some microbial products to subvert production of antigen-specific immune responses. B cell superantigen activity through affinity for BCR carbohydrate is discussed

Direct Gene Transfer for the Understanding and Treatment of Human Disease

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75762/1/j.1749-6632.1994.tb21709.x.pd

Effects of Increased Drought in Amazon Forests Under Climate Change: Separating the Roles of Canopy Responses and Soil Moisture

The Amazon forests are one of the largest ecosystem carbon pools on Earth. Although more frequent and prolonged future droughts have been predicted, the impacts have remained largely uncertain, as most land surface models (LSMs) fail to capture the vegetation drought responses. In this study, the ability of the LSM JSBACH to simulate the drought responses of leaf area index (LAI) and leaf litter production in the Amazon forests is evaluated against artificial drought experiments. Based on the evaluation, improvements are implemented, including a dependency of leaf growth on leaf carbon allocation and a better representation of drought-dependent leaf shedding. The modified JSBACH is shown to capture the drought responses at two sites and across different regions of the basin. It is then coupled with an atmospheric model to simulate the carbon and biogeophysical feedbacks of drought under future climate. We separate the drought impacts into (a) the direct effect, resulting from drier soil and stomatal closure, which does not involve a change in canopy structure, and (b) the LAI effect, resulting from leaf shedding and involving canopy response. We show that the latter accounts for 35% of reduced land carbon uptake (9 ± 10 vs. 26 ± 7 g/m2/yr; mean ± 1 sd) and 12% of surface warming (0.09 ± 0.03 vs. 0.7 ± 0.07 K) during the late 21st century. A north-south dipole of precipitation change is found, which is largely attributable to the direct effect. The results highlight the importance of incorporating drought deciduousness of tropical rainforests in LSMs to better simulate land-atmosphere interactions in the future

Development of a highly protective combination monoclonal antibody therapy against Chikungunya virus

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes global epidemics of a debilitating polyarthritis in humans. As there is a pressing need for the development of therapeutic agents, we screened 230 new mouse anti-CHIKV monoclonal antibodies (MAbs) for their ability to inhibit infection of all three CHIKV genotypes. Four of 36 neutralizing MAbs (CHK-102, CHK-152, CHK-166, and CHK-263) provided complete protection against lethality as prophylaxis in highly susceptible immunocompromised mice lacking the type I IFN receptor (Ifnar−/−) and mapped to distinct epitopes on the E1 and E2 structural proteins. CHK-152, the most protective MAb, was humanized, shown to block viral fusion, and require Fc effector function for optimal activity in vivo. In post-exposure therapeutic trials, administration of a single dose of a combination of two neutralizing MAbs (CHK-102+CHK-152 or CHK-166+CHK-152) limited the development of resistance and protected immunocompromised mice against disease when given 24 to 36 hours before CHIKV-induced death. Selected pairs of highly neutralizing MAbs may be a promising treatment option for CHIKV in humans

Aportes del paleomagnetismo al conocimiento del proceso hidrotermal de Farallón Negro, provincia de Catamarca

Se comparan la dirección y la polaridad de la magnetización remanente estable de zonas con mineralización de cobre porfírico de Farallón Negro con las correspondientes a los cuerpos volcánicos presentes en el Área. Esta comparación indica que dos de las zonas mineralizadas están asociadas genéticamente con los cuerpos riodacíticos, mientras que una lo está con los cuerpos riolíticos. Los datos paleomagnéticos y radimétricos coinciden en indicar que el proceso de mineralización se produjo en distintas fases, las que cubrieron, como mínimo, un lapso del orden de 0.6 m. a.The direction and polarity of the stable remanent magnetization of samples from the mineralization zones of porphyry copper and the volcanic units of Farallón Negro are compared. That indicates that two of the mineralization zones are genetically associated with the rhyodacitic units and one is related with the rhyolitic units. Palaeomagnetic and radiometric data indicate that the mineralization occurred in different phases which span, at least, a period of about 0,6 m.y.Asociación Argentina de Geofísicos y Geodesta