68 research outputs found

    Conservation paleobiology on Minami-Daito Island, Okinawa, Japan: anthropogenic extinction of cave-dwelling bats on a tropical oceanic island

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    Altres ajuts: CERCA Programme/Generalitat de CatalunyaWith strong environmental and geographic filtration, vertebrates incapable of flying and swimming are often extirpated from island ecosystems. Minami-Daito Island is an oceanic island in Okinawa, Japan that harbors the Daito flying fox (Pteropus dasymallus daitoensis), a subspecies of the fruit bat and the only extant mammal endemic to the island. However, the skeleton of a cave-dwelling bat Rhinolophus sp. and fossil guano were briefly reported in a previous study. Here, we present evidence for the anthropogenic extirpation of two species of cave-dwelling bats (Miniopterus sp. & Rhinolophus sp.) from Minami-Daito Island. Our goal is to reliably constrain the ages of the extirpated bat species by a multiproxy approach. Because skeletal materials did not preserve sufficient bone collagen for direct radiocarbon dating, we alternatively examined guano-like deposits based n SEM observation and Fourier-transform infrared spectroscopy (FTIR) along with stable carbon and nitrogen isotope analyses for possible indirect dating. We also examined stable carbon isotopes in bone apatite, assuming that an isotopic signal of C4 plants on the bat bones links to sugarcane plantation on the island based on the historical knowledge that early human settlers quickly replaced the island's native C3 forests with sugarcane (C4 perennial grass) plantation from 1900 onward. Our cave survey documents the remains of Miniopterus sp. from the island for the first time. Based on the unique taphonomic conditions (unpermineralized bones, disarticulated skeletons closely scattered without sediment cover, various degrees of calcite crystal growth around bones) and a radiocarbon age of a humic sample, we suggest that the maximum age constraint of Miniopterus sp. and Rhinolophus sp. is 4,640 calBP. Based on a series of analyses, we conclude that the guano-like deposits are composed not of bat guano but mainly of humic substances; however, a hydroxyapatite crust associated with bat-lying stalagmites may be derived from bat feces. Stable carbon isotope analysis of bone apatite revealed C4 signals in various degrees, confirming that small populations of cave-dwelling bats persisted on Minami-Daito Island after 1900. The results of this study indicate that these populations remained rather small and did not leave many generations and that the estimated ages can be bracketed from 4,640 calBP to the post-1900 (perhaps, until the 1950s). They likely faced a continuously high mortality risk due to severe anthropogenic stresses on the island, where most of the forests were turned into sugarcane plantations within a few decades in the early 20th century. A result of hearing surveys to local residents suggests the latest remnants most likely disappeared on the island concurrently with the introduction of chemical pesticides after World War II

    Regulatory T Cells in Type 1 Autoimmune Pancreatitis

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    Autoimmune pancreatitis (AIP) is a newly recognized pancreatic disorder. Recently, International Consensus Diagnostic Criteria for AIP (ICDC) was published. In this ICDC, AIP was classified into Type 1 and Type 2. Patients with Type 1 AIP have several immunologic and histologic abnormalities specific to the disease, including increased levels of serum IgG4 and storiform fibrosis with infiltration of lymphocytes and IgG4-positive plasmacytes in the involved organs. Among the involved organs showing extrapancreatic lesions, the bile duct is the most common, exhibiting sclerosing cholangitis (IgG4-SC). However, the role of IgG4 is unclear. Recently, it has been reported that regulatory T cells (Tregs) are involved in both the development of various autoimmune diseases and the shift of B cells toward IgG4, producing plasmacytes. Our study showed that Tregs were increased in the pancreas with Type 1 AIP and IgG4-SC compared with control. In the patients with Type 1 AIP and IgG4-SC, the numbers of infiltrated Tregs were significantly positively correlated with IgG4-positive plasma cells. In Type 1 AIP, inducible costimulatory molecule (ICOS)+ and IL-10+ Tregs significantly increased compared with control groups. Our data suggest that increased quantities of ICOS+ Tregs may influence IgG4 production via IL-10 in Type 1 AIP

    Wave propagation in linear electrodynamics

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    The Fresnel equation governing the propagation of electromagnetic waves for the most general linear constitutive law is derived. The wave normals are found to lie, in general, on a fourth order surface. When the constitutive coefficients satisfy the so-called reciprocity or closure relation, one can define a duality operator on the space of the two-forms. We prove that the closure relation is a sufficient condition for the reduction of the fourth order surface to the familiar second order light cone structure. We finally study whether this condition is also necessary.Comment: 13 pages. Phys. Rev. D, to appea

    <i>Spitzer</i> Microlensing Parallax Reveals Two Isolated Stars in the Galactic Bulge

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    We report the mass and distance measurements of two single-lens events from the 2017 Spitzer\textit {Spitzer} microlensing campaign. The ground-based observations yield the detection of finite-source effects, and the microlens parallaxes are derived from the joint analysis of ground-based observations and Spitzer\textit {Spitzer} observations. We find that the lens of OGLE-2017-BLG-1254 is a 0.60 ± 0.03 M ⊙ star with D LS = 0.53 ± 0.11 kpc, where D LS is the distance between the lens and the source. The second event, OGLE-2017-BLG-1161, is subject to the known satellite parallax degeneracy, and thus is either a 0.510.10+0.12M{0.51}_{-0.10}^{+0.12}\,{M}_{\odot } star with D LS = 0.40 ± 0.12 kpc or a 0.380.12+0.13M{0.38}_{-0.12}^{+0.13}\,{M}_{\odot } star with D LS = 0.53 ± 0.19 kpc. Both of the lenses are therefore isolated stars in the Galactic bulge. By comparing the mass and distance distributions of the eight published Spitzer\textit {Spitzer} finite-source events with the expectations from a Galactic model, we find that the Spitzer\textit {Spitzer} sample is in agreement with the probability of finite-source effects occurring in single-lens events

    Managing Phenol Contents in Crop Plants by Phytochemical Farming and Breeding—Visions and Constraints

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    Two main fields of interest form the background of actual demand for optimized levels of phenolic compounds in crop plants. These are human health and plant resistance to pathogens and to biotic and abiotic stress factors. A survey of agricultural technologies influencing the biosynthesis and accumulation of phenolic compounds in crop plants is presented, including observations on the effects of light, temperature, mineral nutrition, water management, grafting, elevated atmospheric CO2, growth and differentiation of the plant and application of elicitors, stimulating agents and plant activators. The underlying mechanisms are discussed with respect to carbohydrate availability, trade-offs to competing demands as well as to regulatory elements. Outlines are given for genetic engineering and plant breeding. Constraints and possible physiological feedbacks are considered for successful and sustainable application of agricultural techniques with respect to management of plant phenol profiles and concentrations

    Oral History Interview with Yuri Fukui, October 19, 1980

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    Interview with Yuri Fukui, a second generation Japanese-American from Oakland, California, about her experience pursuing higher education during the attack on Pearl Harbor and subsequent internment. Fukui discusses the discrimination she experienced in her daily life, struggles faced by her parents, who owned a local business, and life in the internment camps

    Long‐term trends in sex difference in bladder cancer survival 1975‐2009: A population‐based study in Osaka, Japan

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    Abstract In Japan, a study using population‐based cancer registry data from six prefectures revealed a difference in bladder cancer survival between men and women. However, the period of the study was limited to 1993‐2006. The recent introduction of immune checkpoint inhibitors, which have proved to be effective for the treatment for bladder cancer, has led to a rising demand for analysis of long‐term trends in net survival in order to accurately assess the effect of the new treatment. The aim of the present study was to examine long‐term trends in sex difference in bladder cancer net survival using large‐scale population‐based cancer registry data from Osaka, Japan (17,500 cases from 1975 to 2009). We also evaluated sex difference in bladder cancer survival after adjustment for stage, histologic type, and other prognostic factors. We showed the long‐term trend of five‐year net survival for each stage and found that women had poorer five‐year net survival than men for the whole study period. The risk of death from bladder cancer was higher among men than women even after adjusting for period at diagnosis, histologic type, stage, age group, and treatment (Excess hazard ratios: 1.17; 95% Confidence interval: 1.10‐1.25)

    Tocotrienols Prevent the Decline of Learning Ability in High-Fat, High-Sucrose Diet-Fed C57BL/6 Mice

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    Obesity has been increasing worldwide and is well-known as a risk factor for cognitive decline. It has been reported that oxidative stress in the brain is deeply involved in cognitive dysfunction in rodent models. While there are many studies on oxidation in the liver and adipose tissue of obese mice, the relationship between obesity-induced cognitive dysfunction and brain oxidation has not been elucidated. Here, we show that obesity induced by a high-fat, high-sucrose diet (HFSD) alters cognitive function in C57BL/6 male mice, and it may involve the acceleration of brain oxidation. Tocotrienols (T3s), which are members of the vitamin E family, can prevent HFSD-induced cognitive changes. To elucidate these mechanisms, respiratory metabolism, locomotor activity, temperature around brown adipose tissue, and protein profiles in the cerebrum cortex were measured. Contrary to our expectation, respiratory metabolism was decreased, and temperature around brown adipose tissue was increased in the feeding of HFSD. The proteins that regulate redox balance did not significantly change, but 12 proteins, which were changed by HFSD feeding and not changed by T3s-treated HFSD compared to control mice, were identified. Our results indicated that HFSD-induced obesity decreases mouse learning ability and that T3s prevent its change. Additionally, feeding of HFSD significantly increased brain oxidation. However, further study is needed to elucidate the mechanisms of change in oxidative stress in the brain by obesity
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