The Roughness Properties of Small Ice-Bearing Craters at the South Pole of the Moon: Implications for Accessing Fresh Water Ice in Future Surface Operations

The lunar poles provide a fascinating thermal environment capable of cold-trapping water ice on geologic timescales [1]. While there have been many observations indicating the presence of water ice at the lunar surface [e.g., 24], it is still not clear when this ice was delivered to the Moon. The timing of volatile dep-osition provides important constraints on the origin of lunar ice because different delivery mechanisms have been active at different times throughout lunar history. We previously found that some small (<10 km) cra-ters at the south pole of the Moon have morphologies suggestive of relatively young ages, on the basis of crisp crater rims [5]. These craters are too small to date with robust cratering statistics [5], but the possibility of ice in young craters is intriguing because it suggests that there is some recent and perhaps ongoing mechanism that is delivering or redistributing water to polar cold traps. Therefore, understanding if these small, ice-bear-ing craters are indeed young is essential in understand-ing the age and source of volatiles on the Moon. Here we take a new approach to understand the ages of these small polar cold traps: analyzing the roughness properties of small ice-bearing craters. It is well under-stood that impact crater properties (e.g., morphology, rock abundance, and roughness) evolve with time due to a variety of geologic and space-weathering processes [611]. Topographic roughness is a measurement of the local deviation from the mean topography, providing a measurement of surface texture, and is a powerful tool for evaluating surface evolution over geologic time [e.g., 1114]. In this study we analyze the roughness of southern lunar craters (40S90S) from all geologic eras, and determine how the roughness of small (<10 km) ice-bearing craters compare. We discuss the implications of the ages of ice-bearing south polar craters, and potential strategies for accessing fresh ice on the Moon

Targeting hyperarousal: Mantram Repetition Program for PTSD in US veterans.

Background: Hyperarousal appears to play an important role in the development and maintenance of posttraumatic stress disorder (PTSD) symptoms, but current evidence-based treatments appear to address this symptom type less effectively than the other symptom clusters. The Mantram Repetition Program (MRP) is a meditation-based intervention that has previously been shown to improve symptoms of posttraumatic stress disorder (PTSD) and may be especially helpful for hyperarousal. If MRP is an effective tool for decreasing this often treatment-resistant symptom cluster, it may become an important clinical tool. Objective: The goal of this secondary analysis was to examine the effect of the MRP on hyperarousal and other PTSD symptom clusters and to examine hyperarousal as a mediator of treatment response. Method: Secondary analyses were conducted on data from a randomized controlled trial in which Veterans with PTSD (n = 173) were assigned to the MRP or a non-specific psychotherapy control and assessed pre-treatment, post-treatment and 8 weeks after treatment completion. The impact of the interventions on PTSD symptom clusters was examined, and time-lagged hierarchical linear modelling was applied to examine alternative mediation models. Results: All PTSD symptom clusters improved in both treatments. MRP led to greater reductions in hyperarousal at post-treatment (Hedge's g = 0.57) and follow-up (Hedge's g = 0.52), and in numbing at post-treatment (Hedge's g = 0.47). Hyperarousal mediated reductions in the composite of the other PTSD symptom clusters. Although the reverse model was significant as well, the effect was weaker in this direction. Conclusion: Interventions focused on the management of hyperarousal may play an important role in recovery from PTSD. The MRP appears efficacious in reducing hyperarousal, and thereby impacting other PTSD symptom clusters, as one pathway to facilitating recovery

Selection of high-z supernovae candidates

Deep, ground based, optical wide-field supernova searches are capable of detecting a large number of supernovae over a broad redshift range up to z~1.5. While it is practically unfeasible to obtain spectroscopic redshifts of all the supernova candidates right after the discovery, we show that the magnitudes and colors of the host galaxies, as well as the supernovae, can be used to select high-z supernova candidates, for subsequent spectroscopic and photometric follow-up. Using Monte-Carlo simulations we construct criteria for selecting galaxies in well-defined redshift bands. For example, with a selection criteria using B-R and R-I colors we are able to pick out potential host galaxies for which z>0.85 with 80% confidence level and with a selection efficiency of 64-86%. The method was successfully tested using real observations from the HDF. Similarly, we show that that the magnitude and colors of the supernova discovery data can be used to constrain the redshift. With a set of cuts based on V-R and R-I in a search to m_I~25, supernovae at z~1 can be selected in a redshift interval sigma_z <0.15.Comment: 33 pages, 13 figures, accepted for publication in PASP (March 2002 issue

On Topological Susceptibility, Vacuum Energy and Theta Dependence in Gluodynamics

We suggest that the topological susceptibility in gluodynamics can be found in terms of the gluon condensate using renormalizability and heavy fermion representation of the anomaly. Analogous relations can be also obtained for other zero momentum correlation functions involving the topological density operator. Using these relations, we find the theta dependence of the condensates , and of the partition function for small theta and an arbitrary number of colors.Comment: Details of the derivation are clarified, changes in discussions, new references are adde

Contact Term, its Holographic Description in QCD and Dark Energy

In this work we study the well known contact term, which is the key element in resolving the so-called $U(1)_A$ problem in QCD. We study this term using the dual Holographic Description. We argue that in the dual picture the contact term is saturated by the D2 branes which can be interpreted as the tunnelling events in Minkowski space-time. We quote a number of direct lattice results supporting this identification. We also argue that the contact term receives a Casimir -like correction \sim (\Lqcd R)^{-1} rather than naively expected \exp(-\Lqcd R) when the Minkowski space-time ${\cal R}_{3,1}$ is replaced by a large but finite manifold with a size $R$. Such a behaviour is consistent with other QFT-based computations when power like corrections are due to nontrivial properties of topological sectors of the theory. In holographic description such a behaviour is due to massless Ramond-Ramond (RR) field living in the bulk of multidimensional space when power like corrections is a natural outcome of massless RR field. In many respects the phenomenon is similar to the Aharonov -Casher effect when the "modular electric field" can penetrate into a superconductor where the electric field is exponentially screened. The role of "modular operator" from Aharonov -Casher effect is played by large gauge transformation operator $\cal{T}$ in 4d QCD, resulting the transparency of the system to topologically nontrivial pure gauge configurations. We discuss some profound consequences of our findings. In particular, we speculate that a slow variation of the contact term in expanding universe might be the main source of the observed Dark Energy.Comment: Final version to appear in Phys. Rev. D. Comments added on interpretation of the "topological Casimir effect" from 5d viewpoint where it can be thought as conventional Casimir effec

The Gauge Fields and Ghosts in Rindler Space

We consider 2d Maxwell system defined on the Rindler space with metric ds^2=\exp(2a\xi)\cdot(d\eta^2-d\xi^2) with the goal to study the dynamics of the ghosts. We find an extra contribution to the vacuum energy in comparison with Minkowski space time with metric ds^2= dt^2-dx^2. This extra contribution can be traced to the unphysical degrees of freedom (in Minkowski space). The technical reason for this effect to occur is the property of Bogolubov's coefficients which mix the positive and negative frequencies modes. The corresponding mixture can not be avoided because the projections to positive -frequency modes with respect to Minkowski time t and positive -frequency modes with respect to the Rindler observer's proper time \eta are not equivalent. The exact cancellation of unphysical degrees of freedom which is maintained in Minkowski space can not hold in the Rindler space. In BRST approach this effect manifests itself as the presence of BRST charge density in L and R parts. An inertial observer in Minkowski vacuum |0> observes a universe with no net BRST charge only as a result of cancellation between the two. However, the Rindler observers who do not ever have access to the entire space time would see a net BRST charge. In this respect the effect resembles the Unruh effect. The effect is infrared (IR) in nature, and sensitive to the horizon and/or boundaries. We interpret the extra energy as the formation of the "ghost condensate" when the ghost degrees of freedom can not propagate, but nevertheless do contribute to the vacuum energy. Exact computations in this simple 2d model support the claim made in [1] that the ghost contribution might be responsible for the observed dark energy in 4d FLRW universe.Comment: Final version to appear in Phys. Rev. D. Comments on relation with energy momentum computations and few new refs are adde

On Classification of QCD defects via holography

We discuss classification of defects of various codimensions within a holographic model of pure Yang-Mills theories or gauge theories with fundamental matter. We focus on their role below and above the phase transition point as well as their weights in the partition function. The general result is that objects which are stable and heavy in one phase are becoming very light (tensionless) in the other phase. We argue that the $\theta$ dependence of the partition function drastically changes at the phase transition point, and therefore it correlates with stability properties of configurations. Some possible applications for study the QCD vacuum properties above and below phase transition are also discussed.Comment: 21 pages, 2 figure

Prediksi Curah Hujan dengan Menggunakan Algoritma Levenberg-Marquardt dan Backpropagation

Salah satu faktor yang mempengaruhi tipe iklim adalah curah hujan. Keakuratan dalam prediksi curah hujan menjadi faktor penting karena dapat digunakan dalam berbagai kepentingan. Data yang digunakan dalam penelitian ini adalah data curah hujan bulanan, suhu, kelembaban udara, kecepatan angin dan tekanan udara dari tahun 2010 sampai dengan 2014 yang diperoleh dari BMKG Tanjungpinang. Penelitian ini dilakukan dengan membandingkan dua buah algoritma yakni Algoritma Levenberg-Marquardt dan Backpropagation dalam memprediksi curah hujan. Hasil penelitian menunjukan pemodelan dengan Algoritma Levenberg Marquardt memberikan hasil terbaik pada pemodelan data dengan jumlah neuron hidden layer 10, Epoch 100, dengan nilai mse sebesar 0.0776. Sedangkan Algoritma Backpropagation jumlah neuron hidden layer 4, Epoch 1.000 dengan nilai mse sebesar 0.07876. Penelitian ini menunjukkan bahwa perbandingan hasil prediksi curah hujan dengan menggunakan Algoritma Levenberg Marquardt menghasilkan prediksi yang lebih baik dibanding dengan Algoritma Backpropagation

Large-Scale Magnetic Fields, Dark Energy and QCD

Cosmological magnetic fields are being observed with ever increasing correlation lengths, possibly reaching the size of superclusters, therefore disfavouring the conventional picture of generation through primordial seeds later amplified by galaxy-bound dynamo mechanisms. In this paper we put forward a fundamentally different approach that links such large-scale magnetic fields to the cosmological vacuum energy. In our scenario the dark energy is due to the Veneziano ghost (which solves the $U(1)_A$ problem in QCD). The Veneziano ghost couples through the triangle anomaly to the electromagnetic field with a constant which is unambiguously fixed in the standard model. While this interaction does not produce any physical effects in Minkowski space, it triggers the generation of a magnetic field in an expanding universe at every epoch. The induced energy of the magnetic field is thus proportional to cosmological vacuum energy: $\rho_{EM}\simeq B^2 \simeq (\frac{\alpha}{4\pi})^2 \rho_{DE}$, $\rho_{DE}$ hence acting as a source for the magnetic energy $\rho_{EM}$. The corresponding numerical estimate leads to a magnitude in the nG range. There are two unique and distinctive predictions of our proposal: an uninterrupted active generation of Hubble size correlated magnetic fields throughout the evolution of the universe; the presence of parity violation on the enormous scales $1/H$, which apparently has been already observed in CMB. These predictions are entirely rooted into the standard model of particle physics.Comment: jhep style, 22 pages, v2 with updated estimates and extended discussion on parity violation, v3 as published (references updated

Patterns of age-specific mortality in children in endemic areas of sub-Saharan Africa.

Understanding of the age- and season- dependence of malaria mortality is an important prerequisite for epidemiologic models of malaria immunity. However, most studies of malaria mortality have aggregated their results into broad age groups and across seasons, making it hard to predict the likely impact of interventions targeted at specific age groups of children. We present age-specific mortality rates for children aged < 15 years for the period of 2001-2005 in 7 demographic surveillance sites in areas of sub-Saharan Africa with stable endemic Plasmodium falciparum malaria. We use verbal autopsies (VAs) to estimate the proportion of deaths by age group due to malaria, and thus calculate malaria-specific mortality rates for each site, age-group, and month of the year. In all sites a substantial proportion of deaths (ranging from 20.1% in a Mozambican site to 46.2% in a site in Burkina Faso) were attributed to malaria. The overall age patterns of malaria mortality were similar in the different sites. Deaths in the youngest children (< 3 months old) were only rarely attributed to malaria, but in children over 1 year of age the proportion of deaths attributed to malaria was only weakly age-dependent. In most of the sites all-cause mortality rates peaked during the rainy season, but the strong seasonality in malaria transmission in these sites was not reflected in strong seasonality in the proportion of deaths attributed to malaria, except in the two sites in Burkina Faso. Improvement in the specificity of malaria verbal autopsies would make it easier to interpret the age and season patterns in such data