Development and validation of a cryogenic far-infrared diffraction grating spectrometer used to post-disperse the output from a Fourier transform spectrometer

Recent advances in far-infrared detector technology have led to increases in raw sensitivity of more than an order of magnitude over previous state-of-the-art detectors. With such sensitivity, photon noise becomes the dominant noise component, even when using cryogenically cooled optics, unless a method of restricting the spectral bandpass is employed. The leading instrument concept features reflecting diffraction gratings, which post-disperse the light that has been modulated by a polarizing Fourier transform spectrometer (FTS) onto a detector array, thereby reducing the photon noise on each detector. This paper discusses the development of a cryogenic (4 K) diffraction grating spectrometer that operates over the wavelength range of 285 to 500 μm and was used to post-disperse the output from a room-temperature polarizing FTS. Measurements of the grating spectral response and diffraction efficiency are presented as a function of both wavelength and polarization to characterize the instrumental performance

In-orbit performance of the Herschel/SPIRE imaging Fourier transform spectrometer: lessons learned

The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on board the European Space Agency's Herschel Space Observatory which ended its operational phase on 29 April 2013. The low to medium resolution spectroscopic capability of SPIRE is provided by an imaging Fourier transform spectrometer (iFTS) of the Mach-Zehnder configuration. With their high throughput, broad spectral coverage, and variable resolution, coupled with their well-defined instrumental line shape and intrinsic wavelength and intensity calibration, iFTS are becoming increasingly common in far-infrared space astronomy missions. The performance of the SPIRE imaging spectrometer will be reviewed and example results presented. The lessons learned from the measured performance of the spectrometer as they apply to future missions will be discussed

Progress in the Critical Assessment for a Far-Infrared Space Interferometer with Double Fourier Modulation (FP7-FISICA)

The progress and results of the ongoing FP7-FISICA programme to re-asses the scientific goals of a Far-Infrared Space Interfereometer and push the development of some of its key technology elements are reported

Study on the Confirmation and a Variation of Slide Culture Method (S. C. M.) (【5th. Division】 Division of Biological Chemistry)

The progress and results of the ongoing FP7-FISICA programme to re-asses the scientific goals of a Far-Infrared Space Interfereometer and push the development of some of its key technology elements are reported

The (not so) controversial role of DNA methylation in epigenetic inheritance across generations.

It has been demonstrated originally in plants that phenotypic traits, such as floral symmetry, can be caused by changes of methylation patterns of specific genes. Such traits can be transgenerationally inherited for multiple generations and remain associated with cytosine methylation patterns. Whether genomic methylation may also contribute to epigenetic inheritance across generations in vertebrates and notably in mammals is still more controversial. One reason for this tentativeness is the dual occurrence of global genomic de-methylation first in pre-implantation embryos and subsequently in primordial germ cells (PGCs) of mammals. Although gene focused cases of epigenetic inheritance associated with genomic DNA methylation have been well studied mostly in rodents (such as imprinted genes and the Agouti viable yellow, Avy, allele), it is still a matter of debate whether genomic DNA methylation may provide a more general mechanism for the epigenetic inheritance of acquired traits across generations. We review the current literature on this topic with a focus on the potential role of DNA methylation for epigenetic inheritance across generations in mammals

Importance of Baseline Prognostic Factors With Increasing Time Since Initiation of Highly Active Antiretroviral Therapy: Collaborative Analysis of Cohorts of HIV-1-Infected Patients

Background: The extent to which the prognosis for AIDS and death of patients initiating highly active antiretroviral therapy (HAART) continues to be affected by their characteristics at the time of initiation (baseline) is unclear. Methods: We analyzed data on 20,379 treatment-naive HIV-1- infected adults who started HAART in 1 of 12 cohort studies in Europe and North America (61,798 person-years of follow-up, 1844 AIDS events, and 1005 deaths). Results: Although baseline CD4 cell count became less prognostic with time, individuals with a baseline CD4 count 350 cells/μL (hazard ratio for AIDS = 2.3, 95% confidence interval [CI]: 1.0 to 2.3; mortality hazard ratio = 2.5, 95% CI: 1.2 to 5.5, 4 to 6 years after starting HAART). Rates of AIDS were persistently higher in individuals who had experienced an AIDS event before starting HAART. Individuals with presumed transmission by means of injection drug use experienced substantially higher rates of AIDS and death than other individuals throughout follow-up (AIDS hazard ratio = 1.6, 95% CI: 0.8 to 3.0; mortality hazard ratio = 3.5, 95% CI: 2.2 to 5.5, 4 to 6 years after starting HAART). Conclusions: Compared with other patient groups, injection drug users and patients with advanced immunodeficiency at baseline experience substantially increased rates of AIDS and death up to 6 years after starting HAART