Weighing the Quiescent Central Black Hole in an Elliptical Galaxy with X-ray Emitting Gas

We present a Chandra study of the hot ISM in the giant elliptical galaxy NGC4649. In common with other group-centred ellipticals, its temperature profile rises with radius in the outer parts of the galaxy, from ~0.7keV at 2kpc to ~0.9keV by 20kpc. However, within the central ~2kpc the trend reverses and the temperature peaks at ~1.1keV within the innermost 200pc. Under the assumption of hydrostatic equilibrium, we demonstrate that the central temperature spike arises due to the gravitational influence of a quiescent central super-massive black hole. We constrain the black hole mass (MBH) to $(3.35^{+0.67}_{-0.95})\times 10^9$Msun (90% confidence), in good agreement with stellar kinematics measurements. This is the first direct measurement of MBH based on studies of hydrostatic X-ray emitting gas, which are sensitive to the most massive black holes, and is a crucial validation of both mass-determination techniques. This agreement clearly demonstrates the gas must be close to hydrostatic, even in the very centre of the galaxy, which is consistent with the lack of morphological disturbances in the X-ray image. NGC4649 is now one of only a handful of galaxies for which MBH has been measured by more than one method. At larger radii, we were able to decompose the gravitating mass profile into stellar and dark matter (DM) components. Unless one accounts for the DM, a standard Virial analysis of the stars dramatically over-estimates the stellar mass of the galaxy. We find the measured J-band stellar mass-to-light ratio, 1.37+/-0.10 Msun/Lsun, is in good agreement with simple stellar population model calculations for this object.Comment: 13 pages, 6 figures, accepted for publication in ApJ. Minor revisions to match published versio

AGN-Induced Cavities in NGC 1399 and NGC 4649

We present an analysis of archival Chandra and VLA observations of the E0 galaxy NGC 1399 and the E2 galaxy NGC 4649 in which we investigate cavities in the surrounding X-ray emitting medium caused by the central AGN. We calculate the jet power required for the AGN to evacuate these cavities and find values of ~8x10^{41} erg/s and ~14x10^{41} erg/s for the lobes of NGC 1399 and ~7x10^{41} erg/s and ~6x10^{41} erg/s for those of NGC 4649. We also calculate the k/f values for each cavity, where k is the ratio of the total particle energy to that of electrons radiating in the range of 10 MHz to 10 GHz, and f is the volume filling factor of the plasma in the cavity. We find that the values of k/f for the lobes of NGC 1399 are ~93 and ~190, and those of the lobes of NGC 4649 are ~15000 and ~12000. We conclude that the assumed spectrum describes the electron distribution in the lobes of NGC 1399 reasonably well, and that there are few entrained particles. For NGC 4649, either there are many entrained particles or the model spectrum does not accurately describe the population of electrons.Comment: 8 pages, 2 figures, accepted for publication in MNRA

A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2

The cryogenic dark matter experiment CRESST-II aims at the direct detection of WIMPs via elastic scattering off nuclei in scintillating CaWO$_4$ crystals. We present a new, highly improved, detector design installed in the current run of CRESST-II Phase 2 with an efficient active rejection of surface-alpha backgrounds. Using CaWO$_4$ sticks instead of metal clamps to hold the target crystal, a detector housing with fully-scintillating inner surface could be realized. The presented detector (TUM40) provides an excellent threshold of ${\sim}\,0.60\,$keV and a resolution of $\sigma\,{\approx}\,0.090$ keV (at 2.60$\,$keV). With significantly reduced background levels, TUM40 sets stringent limits on the spin-independent WIMP-nucleon scattering cross section and probes a new region of parameter space for WIMP masses below 3$\,$GeV/c$^2$. In this paper, we discuss the novel detector design and the surface-alpha event rejection in detail.Comment: 9 pages, 6 figure

The polymer phase of the TDAE-C60_{60} organic ferromagnet

The high-pressure Electron Spin Resonance (ESR) measurements were preformed on TDAE-C$_{60}$ single crystals and stability of the polymeric phase was established in the $P - T$ parameter space. At 7 kbar the system undergoes a ferromagnetic to paramagnetic phase transition due to the pressure-induced polymerization. The polymeric phase remains stable after the pressure release. The depolymerization of the pressure-induced phase was observed at the temperature of 520 K. Below room temperature, the polymeric phase behaves as a simple Curie-type insulator with one unpaired electron spin per chemical formula. The TDAE$^+$ donor-related unpaired electron spins, formerly ESR-silent, become active above the temperature of 320 K and the Curie-Weiss behavior is re-established.Comment: Submitted to Phys. Rev.

An increase in fat-free mass is associated with higher appetite and energy intake in older adults: a randomised control trial

Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg·m2) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults

Two-Dimensional Infrared Spectroscopy of Antiparallel β-Sheet Secondary Structure

We investigate the sensitivity of femtosecond Fourier transform two-dimensional infrared spectroscopy to protein secondary structure with a study of antiparallel β-sheets. The results show that 2D IR spectroscopy is more sensitive to structural differences between proteins than traditional infrared spectroscopy, providing an observable that allows comparison to quantitative models of protein vibrational spectroscopy. 2D IR correlation spectra of the amide I region of poly-L-lysine, concanavalin A, ribonuclease A, and lysozyme show cross-peaks between the IR-active transitions that are characteristic of amide I couplings for polypeptides in antiparallel hydrogen-bonding registry. For poly-L-lysine, the 2D IR spectrum contains the eight-peak structure expected for two dominant vibrations of an extended, ordered antiparallel β-sheet. In the proteins with antiparallel β-sheets, interference effects between the diagonal and cross-peaks arising from the sheets, combined with diagonally elongated resonances from additional amide transitions, lead to a characteristic “Z”-shaped pattern for the amide I region in the 2D IR spectrum. We discuss in detail how the number of strands in the sheet, the local configurational disorder in the sheet, the delocalization of the vibrational excitation, and the angle between transition dipole moments affect the position, splitting, amplitude, and line shape of the cross-peaks and diagonal peaks.

Abstinence-Only Education and Teen Pregnancy Rates: Why We Need Comprehensive Sex Education in the U.S

The United States ranks first among developed nations in rates of both teenage pregnancy and sexually transmitted diseases. In an effort to reduce these rates, the U.S. government has funded abstinence-only sex education programs for more than a decade. However, a public controversy remains over whether this investment has been successful and whether these programs should be continued. Using the most recent national data (2005) from all U.S. states with information on sex education laws or policies (N = 48), we show that increasing emphasis on abstinence education is positively correlated with teenage pregnancy and birth rates. This trend remains significant after accounting for socioeconomic status, teen educational attainment, ethnic composition of the teen population, and availability of Medicaid waivers for family planning services in each state. These data show clearly that abstinence-only education as a state policy is ineffective in preventing teenage pregnancy and may actually be contributing to the high teenage pregnancy rates in the U.S. In alignment with the new evidence-based Teen Pregnancy Prevention Initiative and the Precaution Adoption Process Model advocated by the National Institutes of Health, we propose the integration of comprehensive sex and STD education into the biology curriculum in middle and high school science classes and a parallel social studies curriculum that addresses risk-aversion behaviors and planning for the future

An Increase in Fat-Free Mass is Associated with Higher Appetite and Energy Intake in Older Adults: A Randomised Control Trial

Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg∙m2) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults

A meta-analysis of long-term effects of conservation agriculture on maize grain yield under rain-fed conditions

Conservation agriculture involves reduced tillage, permanent soil cover and crop rotations to enhance soil fertility and to supply food from a dwindling land resource. Recently, conservation agriculture has been promoted in Southern Africa, mainly for maize-based farming systems. However, maize yields under rain-fed conditions are often variable. There is therefore a need to identify factors that influence crop yield under conservation agriculture and rain-fed conditions. Here, we studied maize grain yield data from experiments lasting 5 years and more under rain-fed conditions. We assessed the effect of long-term tillage and residue retention on maize grain yield under contrasting soil textures, nitrogen input and climate. Yield variability was measured by stability analysis. Our results show an increase in maize yield over time with conservation agriculture practices that include rotation and high input use in low rainfall areas. But we observed no difference in system stability under those conditions. We observed a strong relationship between maize grain yield and annual rainfall. Our meta-analysis gave the following findings: (1) 92% of the data show that mulch cover in high rainfall areas leads to lower yields due to waterlogging; (2) 85% of data show that soil texture is important in the temporal development of conservation agriculture effects, improved yields are likely on well-drained soils; (3) 73% of the data show that conservation agriculture practices require high inputs especially N for improved yield; (4) 63% of data show that increased yields are obtained with rotation but calculations often do not include the variations in rainfall within and between seasons; (5) 56% of the data show that reduced tillage with no mulch cover leads to lower yields in semi-arid areas; and (6) when adequate fertiliser is available, rainfall is the most important determinant of yield in southern Africa. It is clear from our results that conservation agriculture needs to be targeted and adapted to specific biophysical conditions for improved impact