抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

The highly radiopure ≃ 250 kg NaI(Tl) DAMA/LIBRA set-up is running at the Gran Sasso National Laboratory of the INFN. In this paper the first result obtained by exploiting the model independent annual modulation signature for Dark Matter (DM) particles is presented. It refers to an exposure of 0.53 ton×yr. The collected DAMA/LIBRA data satisfy all the many peculiarities of the DM annual modulation signature. Neither systematic effects nor side reactions able to account for the observed modulation amplitude and to contemporaneously satisfy all the several requirements of this DM signature are available. Considering the former DAMA/NaI and the present DAMA/LIBRA data all together (total exposure 0.82 ton×yr), the presence of Dark Matter particles in the galactic halo is supported, on the basis of the DM annual modulation signature, at 8.2 σ C.L.; in particular, in the energy interval (2–6) keV, the modulation amplitude is (0.0131±0.0016) cpd/kg/keV and the phase and the period are well compatible with June 2nd and one year, respectively.

/pdf/first-results-from-dama-libra-and-the-combined-results-with-2w3gda5b82.pdf

First results from DAMA/LIBRA and the combined results with DAMA/NaI

A Viking Lander 1 image was modeled as mixtures of reflectance spectra of palagonite dust, gray andesitelike rock, and a coarse rocklike soil. The rocks are covered to varying degrees by dust but otherwise appear unweathered. Rocklike soil occurs as lag deposits in deflation zones around stones and on top of a drift and as a layer in a trench dug by the lander. This soil probably is derived from the rocks by wind abrasion and/or spallation. Dust is the major component of the soil and covers most of the surface. The dust is unrelated spectrally to the rock but is equivalent to the global-scale dust observed telescopically. A new method was developed to model a multispectral image as mixtures of end-member spectra and to compare image spectra directly with laboratory reference spectra. The method for the first time uses shade and secondary illumination effects as spectral end-members; thus the effects of topography and illumination on all scales can be isolated or removed. The image was calibrated absolutely from the laboratory spectra, in close agreement with direct calibrations. The method has broad applications to interpreting multispectral images, including satellite images.

Spectral mixture modeling - A new analysis of rock and soil types at the Viking Lander 1 site. [on Mars]

DAMA/LIBRA is running at the Gran Sasso National Laboratory of the I.N.F.N. Here the results obtained with a further exposure of 0.34 ton x yr are presented. They refer to two further annual cycles collected one before and one after the first DAMA/LIBRA upgrade occurred on September/October 2008. The cumulative exposure with those previously released by the former DAMA/NaI and by DAMA/LIBRA is now 1.17 ton x yr, corresponding to 13 annual cycles. The data further confirm the previous positive results obtained investigating the presence of Dark Matter (DM) particles in the galactic halo by means of the model independent Dark Matter annual modulation signature; the confidence level is now 8.9 sigma for the cumulative exposure. In particular, with the cumulative exposure the modulation amplitude of the single-hit events in the (2-6) keV energy interval measured in NaI(Tl) target is (0.0116 +/- 0.0013) cpd/kg/keV; the measured phase is (146 +/- 7) days and the measured period is (0.999 +/- 0.002) yr, values well in agreement with those expected for the DM particles.

/pdf/new-results-from-dama-libra-52g07q3znk.pdf

New Results from DAMA/LIBRA.

Estimates of the amount of water outgassed from Mars, based on the composition of the atmosphere, range from 6 to 160 m, as compared with 3 km for the Earth. In contrast, large flood features, valley networks, and several indicators of ground ice suggest that at least 500 m of water have outgassed. The two sets of estimates may be reconciled if early in its history, Mars lost part of its atmosphere by impact erosion and hydrodynamic escape.

Water on Mars

A phenomenological model for the evaluation of the relativistic corrections and other nonstandard effects in the3He photodisintegration sum rules is presented.

Relativistic corrections to3He photodisintegration sum rules

Investigating Vesta's Marcia crater with Dawn data

Comet 67P is shown to be everywhere rich in organic materials with little to no water ice visible on the surface.
In the range of heliocentric distances from 3.59 to 2.74 AU, daytime observed surface temperatures retrieved
from VIRTIS data are overall comprised in the range between 180 and 220 K, which is incompatible with large
exposures of water ice and is consistent with a low-albedo, organics-rich surface. The accuracy of temperature
retrieval is as good as a few K in regions of the comet unaffected by shadowing or limb proximity. Maximum
temperature values as high as 230 K have been recorded in very few places. The highest values of surface
temperature in the early Mapping phase were obtained in August 2014, during observations at small phase angles
implying that the observed surface has a large predominance of small incidence angles, and local solar times
(LST) centered around the maximum daily insolation. In all cases, direct correlation with topographic features is
observed, i.e. largest temperature values are generally associated with the smallest values of illumination angles.
So far, there is no evidence of thermal anomalies, i.e. places of the surface that are intrinsically warmer or cooler
than surrounding terrains observed at the same local solar time and under similar solar illumination.
For a given LST, the maximum temperature mainly depends on the solar incidence angle and on surface properties
such as thermal inertia and albedo. Since VIRTIS is able to observe the same point of the surface on various
occasions under different conditions of solar illumination and LST, it is possible to reconstruct the temperature
of that point at different times of the comet’s day, thus building diurnal profiles of temperature that are useful to
constrain thermal inertia.
The availability of spatially-resolved, accurate temperature observations, significantly spaced out in local solar
time, provides clues to the physical structure local features, which complements the compositional investigation
based on imaging spectroscopy data collected at shorter wavelengths.
In the VIRTIS thermal images, a note of great interest is provided by the ‘neck’ of the comet close to the ‘body’,
where, because of the concave shape, the ‘head’ casts prominent shadows on some areas when they experience
maximum daily insolation. This is a place potentially subjected to considerable thermal stresses. We evaluate both
the spatial thermal gradients and the temporal thermal gradients, providing implications for the surface structure.

Comet 67P: Thermal Maps and Local Properties as Derived from Rosetta/VIRTIS data

Preliminary Geological Map of the Ac-H-12 Toharu Quadrangle of Ceres: An Integrated Mapping Study Using Dawn Spacecraft Data

Introduction: On May 2011 Dawn spacecraft started observations of 4 Vesta [1]. The Dawn VIR-MS (VIS and IR Mapping Spectrometer) mapped most of Vesta’s surface in the spectral range of wavelengths 0.255 1.07 μm for the visible (VIS) and 1.02 5.097 μm for the infrared (IR), generating hyperspectral cubes of 432 bands for each channel [2]. Vesta has a basaltic surface: its spectrum has similar characteristics to the HED (howardite, eucrite and diogenite) meteorites and presents strong absorption bands centered near 0.9 μm and 1.9 μm, indicating the presence of ironbearing pyroxenes [3]. By analyzing the whole disk of Vesta as observed during the approach phase, it is possible to have a global overview of its surface.

M. C. De Sanctis

Papers

Relativistic corrections to3He photodisintegration sum rules

Investigating Vesta's Marcia crater with Dawn data

Comet 67P: Thermal Maps and Local Properties as Derived from Rosetta/VIRTIS data

Preliminary Geological Map of the Ac-H-12 Toharu Quadrangle of Ceres: An Integrated Mapping Study Using Dawn Spacecraft Data

Classification of Dawn VIR hyperspectral Data of Vesta