Relationship between magnetic susceptibility and elemental composition of Guano from Solek Cave, West Sumatera

We measured the magnetic properties and geochemistry of guano on a vertical profile from Solek Cave in West Sumatera. The aim of study was to evaluate whether there was a relation between magnetic susceptibility and the elemental composition of guano. Samples were collected at depth every 5 cm a depth of 230 cm where bedrock was reached. Magnetic susceptibility was measured by using susceptibility meter type Bartington MS2B and the element composition of guano samples was measured by X-Ray Fluoroscence (XRF). Percentage frequency dependence magnetic susceptibility was calculated from the percentage ratio of χ lf - χ hf. The results showed that the magnetic susceptibility varied between 86.8 × 10-8 m3/kg to 2204.2 x 10-8 m3/kg. The results of the frequency dependence magnetic susceptibility indicates that the samples were dominated by multi domain magnetic grains. Additionally, guano samples were found to contain several elements such as Mg, Al, Si, Ca, K, P, Fe and Ti. In We find that there is weak correlation between magnetic susceptibility and elemental composition, particularly Fe and Ti. It indirectly shows the presence of authigenic minerals

Stable isotopes of subfossil bat guano as a long-term environmental archive: insights from a Grand Canyon cave deposit

We investigated the utility of subfossil bat guano as a paleoenvironmental archive by comparing elemental ratios and d13C, d15N, and dD values of various simple extracts from bulk material. Solvent-extracted guano yielded consistent C:N and N:H ratios, and d13C values of solvent-extracted guano exhibited strong covariation with dD values, as well as with the d13C values of other simple extracts (bulk guano, bulk lipid). The results suggest that reliable records are easily recovered for d13C, and also indicate that d15N values may have utility as a paleoenvironmental archive. Despite coeval d13C values of bulk guano and solvent-extracted guano, 14C ages of the different fractions did not always yield similar ages, indicating that future refinement of a suitable extraction protocol is required. Applying these protocols to an ancient bat guano deposit allowed us to infer that climate at the Grand Canyon during the late Pleistocene was more variable and generally cooler and wetter, relative to Holocene climate. We conclude that guano deposits are an underutilized, yet powerful continental paleoenvironmental archive of climate change for semi-arid and tropical regions

Magnetic susceptibility and heavy metals in guano from South Sulawesi caves

Measurement of some magnetic properties have been performed on vertical profile from South Sulawesi caves (Mampu and Bubau) by using low cost, rapid, sensitive and non destructive magnetic method. The aim is to attempt to use magnetic characters as a fingerprint for anthropogenic pollution in the caves. Guano samples were collected every 5 cm at a certain section of Mampu and Bubau cave, South Sulawesi, starting from surface through 300 cm in depth of mampu Cave and 30 cm of Bubau Cave. The magnetic parameters such as magnetic susceptibility and percentage frequency dependence susceptibility were measured using the Bartington MS2-MS2B instruments and supported by X-Ray Fluoroscence (XRF) to know their element composition. The results show that the samples had variations in magnetic susceptibility from 3.5 to 242.6 x 10(-8) m(3)/kg for Mampu Cave and from 8.6 to 106.5 x 10(-8) m(3)/kg for Bubau Cave and also magnetic domain. Then, the XRF results show that the caves contain several heavy metals. Magnetic and heavy metal analyses showing that the magnetic minerals in caves are lithogenic (Fe bearingminerals) in origin and anthropogenic (Zn content) in the caves

Climate reconstruction from Barrow Island, Western Australia

Barrow Island ( 20.7°S) is ideally situated to register the first coastal occupations in Australia as well as peoples' responses to major changes in sea level, climate and eventual isolation from critical resources on the mainland. Its location in the arid region between monsoonal and extratropical rainfall belts also imply that Barrow Island may have experienced dramatic changes in precipitation over the period of human occupation. Boodie cave has been the focus of Barrow Island Archeological Project and records a rich record of human occupation. Also present at Boodie cave are significant quantities of water-lain cave carbonates (flowstones, stalactites, and stalagmites). Active (modern) deposition of such carbonates is limited to very small encrustations and consists primarily of stalactites that are less than 5 cm in diameter. This situation indicates that deposition of significant carbonates is indicative of wetter conditions at Barrow Island and dating of these carbonates using the U/Th method provides a record of wet intervals at Barrow Island over the last 120 thousand years. In addition to ages from flowstones, three complete speleothems were collected Ledge Cave for climatic reconstruction using stable isotopes. Ledge cave is large subterranean with high relative humidity (>98%) and abundant, but largely inactive speleothems. The wettest interval in our cave carbonate record predates stratigraphic units with cultural material, but indicates that wet intervals on Barrow Island were broadly coincidental with lake expansions on the Australian mainland. In particular, a very wet interval between 120 and 90 ka is recorded in two of the Ledge Cave speleothems. The Barrow Island speleothem record suggests that displacement of the Intertropical Convergence Zone (ITCZ) and the strength of the Indo-Australian monsoon may have been the most important influence on water balance at Barrow Island. Continued development of these climate archives will offer insights into climate that is directly applicable to the unique human occupation record also preserved at this site

STAT5 drives abnormal proliferation in autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) leads to renal failure. The hallmark of ADPKD is increased epithelial proliferation, which has been proposed to be due to atypical signaling including abnormal JAK-STAT activity. However, the relative contribution of JAK-STAT family members in promoting proliferation in ADPKD is unknown. Here, we present siRNA JAK-STAT-focused screens discovering a previously unknown proliferative role for multiple JAK-STAT components (including STAT1, STAT2, STAT4, STAT5a, and STAT5b). Amongst these, we selected to study the growth hormone/growth hormone receptor/STAT5-axis because of its known role as a regulator of growth in nonrenal tissues. Loss of STAT5 function, facilitated by pharmacological inhibition or siRNAs, significantly reduced proliferation with an associated reduction in cyst growth in vitro. To study whether STAT5 is abnormally activated in vivo, we analyzed its expression using two independent mouse models of ADPKD. STAT5 was nuclear, thus activated, in renal epithelial cyst lining cells in both models. To test whether forced activation of STAT5 can modulate proliferation of renal cells in vivo, irrespective of the Pkd1 status, we overexpressed growth hormone. These mice showed increased STAT5 activity in renal epithelial cells, which correlated with de novo expression of cyclin D1, a STAT5 target gene. Chromatin immunoprecipitation experiments revealed that STAT5 transcriptionally activated cyclin D1 in a growth hormone-dependent fashion, thus providing a mechanism into how STAT5 enhances proliferation. Finally, we provide evidence of elevated serum growth hormone in Pkd1 mutant mice. Thus, the growth hormone/STAT5 signaling axis is a novel therapeutic target in ADPKD

Physical Processes in Star Formation

© 2020 Springer-Verlag. The final publication is available at Springer via https://doi.org/10.1007/s11214-020-00693-8.Star formation is a complex multi-scale phenomenon that is of significant importance for astrophysics in general. Stars and star formation are key pillars in observational astronomy from local star forming regions in the Milky Way up to high-redshift galaxies. From a theoretical perspective, star formation and feedback processes (radiation, winds, and supernovae) play a pivotal role in advancing our understanding of the physical processes at work, both individually and of their interactions. In this review we will give an overview of the main processes that are important for the understanding of star formation. We start with an observationally motivated view on star formation from a global perspective and outline the general paradigm of the life-cycle of molecular clouds, in which star formation is the key process to close the cycle. After that we focus on the thermal and chemical aspects in star forming regions, discuss turbulence and magnetic fields as well as gravitational forces. Finally, we review the most important stellar feedback mechanisms.Peer reviewedFinal Accepted Versio

Discovery and functional prioritization of Parkinson's disease candidate genes from large-scale whole exome sequencing.

BACKGROUND: Whole-exome sequencing (WES) has been successful in identifying genes that cause familial Parkinson's disease (PD). However, until now this approach has not been deployed to study large cohorts of unrelated participants. To discover rare PD susceptibility variants, we performed WES in 1148 unrelated cases and 503 control participants. Candidate genes were subsequently validated for functions relevant to PD based on parallel RNA-interference (RNAi) screens in human cell culture and Drosophila and C. elegans models. RESULTS: Assuming autosomal recessive inheritance, we identify 27 genes that have homozygous or compound heterozygous loss-of-function variants in PD cases. Definitive replication and confirmation of these findings were hindered by potential heterogeneity and by the rarity of the implicated alleles. We therefore looked for potential genetic interactions with established PD mechanisms. Following RNAi-mediated knockdown, 15 of the genes modulated mitochondrial dynamics in human neuronal cultures and four candidates enhanced α-synuclein-induced neurodegeneration in Drosophila. Based on complementary analyses in independent human datasets, five functionally validated genes-GPATCH2L, UHRF1BP1L, PTPRH, ARSB, and VPS13C-also showed evidence consistent with genetic replication. CONCLUSIONS: By integrating human genetic and functional evidence, we identify several PD susceptibility gene candidates for further investigation. Our approach highlights a powerful experimental strategy with broad applicability for future studies of disorders with complex genetic etiologies

Intrinsic and extrinsic forcing in life histories: patterns of growth and stable isotopes in male Antarctic fur seal teeth

Life-time records of the trophic sources of carbon, nitrogen and of growth rate can be generated from biogenic structures that show accretionary growth, including fish scales, whale baleen and the teeth of some animals. Records generated from individual teeth can also be combined to provide longer time series elucidating changes in environmental conditions encountered by a population. Both intrinsic (i.e. ontogenetic) and extrinsic (i.e. environmental) factors are important in modulating variation in growth and the apparent dietary sources of C and N. We used the canine teeth of a large marine predator, the male Antarctic fur seal Arctocephalus gazella from South Georgia, to investigate both intrinsic and extrinsic sources of variation. Substantial ontogenetic shifts occurred in both delta C-13 and delta N-15 values in individual teeth, indicating a change in the trophic sources of C and N as individual animals age. Over the 40 yr period from 1964 to 2005, and after statistical reduction of ontogenetic variation, we also detected long-term declines in delta C-13 and delta N-15 values, indicating that the population has become more dependent on energy from a lower trophic level. A concurrent decline in annular tooth growth may be a consequence of rapid population growth during this period. The time series of delta C-13 values was also inversely correlated with sea surface temperatures in the region, although isolating a causal relationship remains elusive. Our analyses suggest that both intrinsic and extrinsic sources of variation, and their interaction, must be considered from Such time series data; failure to do so could result in a biased interpretation

Thermal histories, stress, and metabolic rates of chinook salmon (Oncorhynchus tshawytscha) in Lake Ontario: evidence from intra-otolith stable isotope analyses

We describe thermal histories for Lake Ontario chinook salmon (Oncorhynchus tshawytscha) as determined from otolith δ^sup 18^O thermometry using computer-controlled micromilling techniques to recover otolith aragonite at subseasonal resolution. We find that during the summer months chinook salmon inhabited epilimnetic waters with temperatures of ~19-20 °C as far back as the late 1980s. Chinook would approach but rarely exceed their reported upper incipient lethal limit of approximately 22°C, which suggests that these fish were seeking water with temperatures as high as was tolerable while otolith growth occurred. These results contrast with expected midsummer temperatures for this cold-water salmonine. Bioenergetic simulations indicate significant stress imposed upon chinook salmon. We estimate consumption to be up to 20% more and gross conversion efficiency 18% less annually relative to nominal simulations where chinook salmon are modeled nearer their preferred temperature, reinforcing previous inferences that the chinook salmon population may be near the limits of sustainability. We also find a strong negative correlation between δ^sup 18^O and δ^sup 13^C values. Therefore, seasonal and ontogenetic variation in δ^sup 13^C values of chinook salmon otoliths appear to be related to metabolic rate during pelagic residence and may provide an indirect method for evaluating field activity and other aspects of fish life history