Picking battles: The impact of trust assumptions on the elaboration of security requirements

This position paper describes work on trust assumptions in the con-text of security requirements. We show how trust assumptions can affect the scope of the analysis, derivation of security requirements, and in some cases how functionality is realized. An example shows how trust assumptions are used by a requirements engineer to help define and limit the scope of analysis and to document the decisions made during the process

Genetic solutions through breeding counteract climate change and secure barley production in Australia

Climate changes threaten global sustainable food supply by reducing crop yield. Estimates of future crop production under climate change have rarely considered the capacity of genetic improvement in breeding high-yielding and stress-tolerant crop varieties. We believe that technological advancements and developing climate-resilient crop varieties may offset the adverse effects of climate change. In this study, we examined the historical record of barley breeding and yield, and the trends of climate changes over the past 70 years in Australia. We related the selection of fast development varieties to yield improvement, and revealed the genetic connections of fast development and yield potential through genome-wide association studies. Historical records show that Australia's barley yield has experienced a steady growth despite that the seasonal production window has been shortened due to increased risk of frost damage at flowering stage and terminal heat during maturity since the 1970s. The increase in yield is largely the result of higher yield capacity of the more recently developed varieties that develop faster to counteract the impact of increased terminal heat. We also show that the changing temperature may soon reach a critical point that dramatically changes the barley flowering behaviour to impact yield by pushing its growth beyond the seasonal production window to face increasing frost damage. For the first time, we provide evidence that the effects of climate change on crop production might be less severe than what is currently believed because the advancement of technologies and development of climate-resilient crop varieties may mitigate the adverse effect of climate change to some extent. The greater use of genetic techniques in crop breeding will play a vital role in sustainable global food production in the era of climate change

Tracing the String: BMN correspondence at Finite J^2/N

Employing the string bit formalism of hep-th/0209215, we identify the basis transformation that relates BMN operators in N=4 gauge theory to string states in the dual string field theory at finite g_2=J^2/N. In this basis, the supercharge truncates at linear order in g_2, and the mixing amplitude between 1 and 2-string states precisely matches with the (corrected) answer of hep-th/0206073 for the 3-string amplitude in light-cone string field theory. Supersymmetry then predicts the order g_2^2 contact term in the string bit Hamiltonian. The resulting leading order mass renormalization of string states agrees with the recently computed shift in conformal dimension of BMN operators in the gauge theory.Comment: 11 pages, 1 figur

Non-Fermi liquid behavior and scaling of low frequency suppression in optical conductivity spectra of CaRuO3_3

Optical conductivity spectra $\sigma_1(\omega)$ of paramagnetic CaRuO$_3$ are investigated at various temperatures. At T=10 K, it shows a non-Fermi liquid behavior of $\sigma_1(\omega)\sim 1/{\omega}^{\frac 12}$, similar to the case of a ferromagnet SrRuO$_3$. As the temperature ($T$) is increased, on the other hand, $\sigma_1(\omega)$ in the low frequency region is progressively suppressed, deviating from the 1/{\omega}^{\frac 12%}-dependence. Interestingly, the suppression of $\sigma_1(\omega)$ is found to scale with $\omega /T$ at all temperatures. The origin of the $$ scaling behavior coupled with the non-Fermi liquid behavior is discussed.Comment: 4 pages, 3 figure

Pointfree factorization of operation refinement

The standard operation refinement ordering is a kind of “meet of op- posites”: non-determinism reduction suggests “smaller” behaviour while increase of definition suggests “larger” behaviour. Groves’ factorization of this ordering into two simpler relations, one per refinement concern, makes it more mathe- matically tractable but is far from fully exploited in the literature. We present a pointfree theory for this factorization which is more agile and calculational than the standard set-theoretic approach. In particular, we show that factorization leads to a simple proof of structural refinement for arbitrary parametric types and ex- ploit factor instantiation across different subclasses of (relational) operation. The prospect of generalizing the factorization to coalgebraic refinement is discussedFundação para a Ciência e a Tecnologia (FCT) - PURE Project (Program Understanding and Re-engineering: Calculi and Applications), contract POSI/ICHS/44304/2002

South-South Irregular Migration: The Impacts of China’s Informal Gold Rush in Ghana

This article examines irregular South‐South migration from China to Ghana, and the role it played in transforming livelihoods and broader developmental landscapes. It looks at the entry of approximately 50,000 Chinese migrants into the informal small‐scale gold mining sector from 2008‐2013. These migrants mainly hailed from Shanglin County in Guangxi Province. In Ghana, they formed mutually beneficial relationships with local miners, both legal and illegal, introducing machinery that substantially increased gold production. However, the legal status of Chinese miners was particularly problematic as, by law, small‐scale mining is restricted to Ghanaian citizens. In mid‐2013, President Mahama established a military task force against illegal mining, resulting in the deportation of many Chinese miners. The article examines the experiences of both Chinese migrants and Ghanaian miners. Findings are that irregular migration into an informal sector had long‐lasting impacts and played a significant role in the transformation of economic, political, and physical landscapes in Ghana

Baryonium, tetra-quark state and glue-ball in large N_c QCD

From the large-N_c QCD point of view, baryonia, tetra-quark states, hybrids, and glueballs are studied. The existence of these states is argued for. They are constructed from baryons. In N_f=1 large N_c QCD, a baryonium is always identical to a glueball with N_c valence gluons. The ground state 0^{-+} glueball has a mass about 2450 MeV. f_0(1710) is identified as the lowest 0^{++} glueball. The lowest four-quark nonet should be f_0(1370), a_0(1450), K^*_0(1430) and f_0(1500). Combining with the heavy quark effective theory, spectra of heavy baryonia and heavy tetra-quark states are predicted. 1/N_c corrections are discussed.Comment: 16 pages, 3 figure

Excitonic Transitions and Off-resonant Optical Limiting in CdS Quantum Dots Stabilized in a Synthetic Glue Matrix

Stable films containing CdS quantum dots of mean size 3.4 nm embedded in a solid host matrix are prepared using a room temperature chemical route of synthesis. CdS/synthetic glue nanocomposites are characterized using high resolution transmission electron microscopy, infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. Significant blue shift from the bulk absorption edge is observed in optical absorption as well as photoacoustic spectra indicating strong quantum confinement. The exciton transitions are better resolved in photoacoustic spectroscopy compared to optical absorption spectroscopy. We assign the first four bands observed in photoacoustic spectroscopy to 1se–1sh, 1pe–1ph, 1de–1dhand 2pe–2phtransitions using a non interacting particle model. Nonlinear absorption studies are done using z-scan technique with nanosecond pulses in the off resonant regime. The origin of optical limiting is predominantly two photon absorption mechanism

Pointfree Factorization of Operation Refinement

The standard operation refinement ordering is a kind of “meet of opposites”: non-determinism reduction suggests “smaller ” behaviour while increase of definition suggests “larger ” behaviour. Groves ’ factorization of this ordering into two simpler relations, one per refinement concern, makes it more mathematically tractable but is far from fully exploited in the literature. We present a pointfree theory for this factorization which is more agile and calculational than the standard set-theoretic approach. In particular, we show that factorization leads to a simple proof of structural refinement for arbitrary parametric types and exploit factor instantiation across different subclasses of (relational) operation. The prospect of generalizing the factorization to coalgebraic refinement is discussed