Dark Matter - Are They Insulators to Electromagnetic Radiation?

The detection of Dark Matter is the greatest outstanding problem in modern cosmology. Several attempts have been taken for this without any remarkable success. To find out a suitable way of detection we need to understand its nature comprehensively. In the present article, a hypothesis is described considering Dark Matter as a normal matter. Its peculiar behavior is explained considering its existence in BEC state in the coolest part of the universe that makes it an electromagnetic insulator. Depending upon this hypothesis an experimental verification method is proposed.

Resonant tunneling in natural photosynthetic systems

The high internal quantum efficiency observed in higher plants remains an outstanding problem in understanding photosynthesis. Several approaches such as quantum entanglement and quantum coherence have been explored. However, none has yet drawn an analogy between superlattices and the geometrical structure of granal thylakoids in leaves. In this paper, we calculate the transmission coefficients and perform numerical simulations using the parameters relevant to a stack of thylakoid discs. We then show that quantum resonant tunneling can occur at low effective mass of particles for 680 nm and 700 nm incident wavelengths corresponding to energies at which photosynthesis occurs.

Polarity symmetry of leaders in moist air

The most important physics underlying lightning is the leader discharge. The presence or absence of space stems/leaders in leader steps is the key to the polarity asymmetry of leaders, which describes the difference in macroscopic behavior between positive and negative leaders and is a long-term consensus among lightning physicists. It is generally believed that negative leader steps are led by space stem, and there is no space stem/leader in positive leader discharges. Here we report the emergence of the space stem and the bidirectional development of the space leader in positive leader steps in moist air, using a high-speed camera with unprecedented spatial-temporal resolution. The lifetime of space stem/leader in positive leader steps is shorter than that in negative leader steps, causing the uncover of space stem/leader in previous studies. The bidirectional development of space leaders in positive leader steps may be an important source for VHF radiations, illuminating insight into the outstanding problem that how positive lightning leaders produce VHF radiation.

Debris cover and the thinning of Kennicott Glacier, Alaska: in situ measurements, automated ice cliff delineation and distributed melt estimates

Many glaciers are thinning rapidly beneath melt-reducing debris cover, including Kennicott Glacier in Alaska where glacier-wide maximum thinning also occurs under debris. This contradiction has been explained by melt hotspots, such as ice cliffs, scattered within the debris cover. However, melt hotspots alone cannot account for the rapid thinning at Kennicott Glacier. We consider the significance of ice cliffs, debris, and ice dynamics in addressing this outstanding problem. We collected abundant in situ measurements of debris thickness, sub-debris melt, and ice cliff backwasting, allowing for extrapolation across the debris-covered tongue (the study area and the lower 24.2 km2 of the 387 km2 glacier). A newly developed automatic ice cliff delineation method is the first to use only optical satellite imagery. The adaptive binary threshold method accurately estimates ice cliff coverage even where ice cliffs are small and debris color varies. Kennicott Glacier exhibits the highest fractional area of ice cliffs (11.7 %) documented to date. Ice cliffs contribute 26 % of total melt across the glacier tongue. Although the relative importance of ice cliffs to area-average melt is significant, the absolute area-averaged melt is dominated by debris. At Kennicott Glacier, glacier-wide melt rates are not maximized in the zone of maximum thinning. Declining ice discharge through time therefore explains the rapid thinning. There is more debris-covered ice in Alaska than in any other region on Earth. Through this study, Kennicott Glacier is the first glacier in Alaska, and the largest glacier globally, where melt across its debris-covered tongue has been rigorously quantified.

Crustal thickening and endogenic oxidation of magmatic sulfur

Porphyry ore deposits, Earth’s most important resources of copper, molybdenum, and rhenium, are strongly associated with felsic magmas showing signs of high-pressure differentiation and are usually found in places with thickened crust (>45 kilometers). This pattern is well-known, but unexplained, and remains an outstanding problem in our understanding of porphyry ore deposit formation. We approach this problem by investigating the oxidation state of magmatic sulfur, which controls the behavior of ore-forming metals during magma differentiation and magmatic-hydrothermal transition. We use sulfur in apatite to reconstruct the sulfur oxidation state in the Gangdese batholith, southern Tibet. We find that magma sulfate content increased abruptly after India-Eurasia collision. Apatite sulfur content and the calculated magma S6+/ΣS ratio correlate with whole-rock dysprosium/ytterbium ratio, suggesting that residual garnet, favored in thickened crust, exerts a first-order control on sulfur oxidation in magmatic orogens. Our findings link sulfur oxidation to internal petrogenic processes and imply an intrinsic relationship of magma oxidation with synmagmatic crustal thickening.

English to Malay Translation of Culture-Specific Items in Selected Penang Tourist Brochures

<em>Translation of Culture-Specific Items (CSIs) is one of the challenges translators face in choosing the appropriate strategies and finding solutions to the translation problems. In this descriptive study four tourist brochures that promoted the UNESCO-heritage Penang Island in Malaysia were analysed. The texts were selected purposefully from Malaysian tourist websites. Based on Newmark’s (1988) model, the CSIs were categorised, and the problems in translation process were described after employing Venuti’s domestication and foreignisation strategies for translating the items. Overall, 76 CSIs were identified in the four brochures among which the most frequent items were Material Culture (65%) with the subcategories of House/City (39%), Food (10%), Transport (15%), and Traditional Weapons (1%). Ecology category built up 13% of the whole items where 5% were related to Fauna and Geographical features, 3% to Flora and 5% to Geographical location. CSIs related to the subcategory of Artistic Thing and Craft formed 8% of the total items. The CSIs related to Social Culture consisted of 13%, including Work (11%), Names and Terms of Address (1%), and Kinship (1%). One outstanding problem during the translation process was finding dynamic equivalence for the words or phrases in the target language (Malay). The findings revealed that domestication strategy and formal equivalence is more appropriate for translating the tourist brochures from English to Malay, which may enhance understanding of linguistically accurate and culturally interesting translation.</em>

Cortical Microcircuits from a Generative Vision Model

Understanding the information processing roles of cortical circuits is an outstanding problem in neuroscience and artificial intelligence. The theoretical setting of Bayesian inference has been suggested as a framework for understanding cortical computation. Based on a recently published generative model for visual inference (George et al., 2017), we derive a family of anatomically instantiated and functional cortical circuit models. In contrast to simplistic models of Bayesian inference, the underlying generative model’s representational choices are validated with real-world tasks that required efficient inference and strong generalization. The cortical circuit model is derived by systematically comparing the computational requirements of this model with known anatomical constraints. The derived model suggests precise functional roles for the feedforward, feedback and lateral connections observed in different laminae and columns, and assigns a computational role for the path through the thalamus.

Short-lived radioisotopes in meteorites from Galactic-scale correlated star formation

Meteoritic evidence shows that the Solar system at birth contained significant quantities of short-lived radioisotopes (SLRs) such as 60Fe and 26Al produced in supernova explosions and in the Wolf-Rayet winds. Explaining how they travelled from these origin sites to the primitive Solar system before decaying is an outstanding problem. In this paper, we present a chemo-hydrodynamical simulation of the entire Milky Way to measure for the distribution of 60Fe/56Fe and 26Al/27Al ratios over all stars in the Galaxy. We show that the Solar abundance ratios are well within the normal range. We find that SLRs are abundant in newborn stars because star formation is correlated on Galactic scales, so that ejecta preferentially enrich atomic gas that will subsequently be accreted onto existing GMCs or will form new ones. Thus new generations of stars preferentially form in patches of the Galaxy contaminated by previous generations of stellar feedback.

All-or-none switching of photon upconversion in self-assembled organogel systems

Aggregation-induced photon upconversion (iPUC) based on a triplet–triplet annihilation (TTA) process is successfully developed via controlled self-assembly of donor–acceptor pairs in organogel nanoassemblies. Although segregation of donor from acceptor assemblies has been an outstanding problem in TTA-based UC and iPUC, we resolved this issue by modifying both the triplet donor and aggregation induced emission (AIE)-type acceptor with glutamate-based self-assembling moieties. These donors and acceptors co-assemble to form organogels without segregation. Interestingly, these donor–acceptor binary gels show upconversion at room temperature but the upconversion phenomena were lost upon dissolution of the gels on heating. The observed changes in TTA-UC emission were thermally reversible, reflecting the controlled assembly/disassembly of the binary molecular systems. The observed on/off ratio of UC emission was much higher than that of the aggregation-induced fluorescence of the acceptor, which highlights the important role of iPUC, i.e., multi-exciton TTA for photoluminescence switching. This work bridges iPUC and supramolecular chemistry and provides a new strategy for designing stimuli-responsive upconversion systems.

A zsarnokölésről, avagy jogszerű-e a zsarnok elpusztítása?

The aim of the essay is to analyse a special moment, namely the moment of the end of a tyranny. An outstanding problem is how to judge the murder of a tyrant, and the occurrences that lead to that, because these acts actually make a chain of crimes, if they’re examined without the context. Breach of the peace, mayhem, mutiny, homicide, these are acts, that are against the moral code of humanity. They have been punished by criminal laws throughout history. Therefore it is crucial to examine the circumstances of this very act. These circumstances are actually the key factors to legitimise the aggression of a rebellion. Nevertheless the first thing that someone has to do during the analysis is to find a comprehensive definition that shows who is the person, who possesses the characteristic of an unjust despot.