Adsorbing staircase polygons subject to a force

We study several models of staircase polygons on the $45^\circ$ rotated square lattice, which interact with an impenetrable surface while also being pushed towards or pulled away from the surface by a force. The surface interaction is governed by a fugacity $a$ and the force by a fugacity $y$. Staircase polygons are simplifications of more general self-avoiding polygons, a well-studied model of interacting ring polymers. For this simplified case we are able to exactly determine the limiting free energy in the full $a$-$y$ plane, and demonstrate that staircase polygons exhibit four different phases, including a "mixed" adsorbed-ballistic phase.Comment: 20 pages, 6 figure

A Quantum Algorithm To Locate Unknown Hashes For Known N-Grams Within A Large Malware Corpus

Quantum computing has evolved quickly in recent years and is showing significant benefits in a variety of fields. Malware analysis is one of those fields that could also take advantage of quantum computing. The combination of software used to locate the most frequent hashes and $n$-grams between benign and malicious software (KiloGram) and a quantum search algorithm could be beneficial, by loading the table of hashes and $n$-grams into a quantum computer, and thereby speeding up the process of mapping $n$-grams to their hashes. The first phase will be to use KiloGram to find the top-$k$ hashes and $n$-grams for a large malware corpus. From here, the resulting hash table is then loaded into a quantum machine. A quantum search algorithm is then used search among every permutation of the entangled key and value pairs to find the desired hash value. This prevents one from having to re-compute hashes for a set of $n$-grams, which can take on average $O(MN)$ time, whereas the quantum algorithm could take $O(\sqrt{N})$ in the number of table lookups to find the desired hash values.Comment: IEEE Quantum Week 2020 Conferenc

The critical surface fugacity of self-avoiding walks on a rotated honeycomb lattice

In a recent paper by Beaton et al, it was proved that a model of self-avoiding walks on the honeycomb lattice, interacting with an impenetrable surface, undergoes an adsorption phase transition when the surface fugacity is $1+\sqrt{2}$. Their proof used a generalisation of an identity obtained by Duminil-Copin and Smirnov, and confirmed a conjecture of Batchelor and Yung. We consider a similar model of self-avoiding walk adsorption on the honeycomb lattice, but with the lattice rotated by $\pi/2$. For this model there also exists a conjecture for the critical surface fugacity, made in 1998 by Batchelor, Bennett-Wood and Owczarek. Using similar methods to Beaton et al, we prove that this is indeed the critical fugacity.Comment: 28 pages, 9 figure

The critical pulling force for self-avoiding walks

Self-avoiding walks are a simple and well-known model of long, flexible polymers in a good solvent. Polymers being pulled away from a surface by an external agent can be modelled with self-avoiding walks in a half-space, with a Boltzmann weight $y = e^f$ associated with the pulling force. This model is known to have a critical point at a certain value $y_c$ of this Boltzmann weight, which is the location of a transition between the so-called free and ballistic phases. The value $y_c=1$ has been conjectured by several authors using numerical estimates. We provide a relatively simple proof of this result, and show that further properties of the free energy of this system can be determined by re-interpreting existing results about the two-point function of self-avoiding walks.Comment: 8 pages, 1 figur

The Staffing of Presidential Assistants: Their Effect on Presidential Success in the House of Representatives

This paper examines the Congressional success of United States Presidents based on the reported Congressional Quarterly Presidential Box Scores. Their individual success is examined as an effect of the senior staff member a President chooses and whether they are chosen from the campaign, personal experience, or previous administrations. It is important for a President to consider the origins of these staffers as these Assistants to the President act as the body of the President’s administration. The econometric analysis presented reveals several interesting results. First, the predominance of a President to choose staff members from his campaign shows no significant impact on his Congressional relations and success. Second, staff members chosen from personal experience have a negatively correlated hindrance on success. Finally, those members chosen for their experience in previous administrations has a positive impact on Presidential success. This research is used to supplement the existing, qualitative research on the subject through regression analysis

Analysis of Extensive [FeFe] Hydrogenase Gene Diversity Within the Gut Microbiota of Insects Representing Five Families of Dictyoptera

We have designed and utilized degenerate primers in the phylogenetic analysis of [FeFe] hydrogenase gene diversity in the gut ecosystems of roaches and lower termites. H2 is an important free intermediate in the breakdown of wood by termite gut microbial communities, reaching concentrations in some species exceeding those measured for any other biological system. The primers designed target with specificity the largest group of enzymatic H domain proteins previously identified in a termite gut metagenome. “Family 3” hydrogenase sequences were amplified from the guts of lower termites, Incisitermes minor, Zootermopsis nevadensis, and Reticulitermes hesperus, and two roaches, Cryptocercus punctulatus and Periplaneta americana. Subsequent analyses revealed that all termite and Cryptocercus sequences were phylogenetically distinct from non-termiteassociated hydrogenases available from public databases. The abundance of unique sequence operational taxonomic units (as many as 21 from each species) underscores the previously demonstrated physiological importance of H2 to the gut ecosystems of these wood-feeding insects. The diversity of sequences observed might be reflective of multiple niches that the enzymes have been evolved to accommodate. Sequences cloned from Cryptocercus and the lower termite samples, all of which are wood feeding insects, clustered closely with one another in phylogenetic analyses to the exclusion of alleles from P. americana, an omnivorous cockroach, also cloned during this study. We present primers targeting a family of termite gut [FeFe] hydrogenases and provide results that are consistent with a pivotal role for hydrogen in the termite gut ecosystem and point toward unique evolutionary adaptations to the gut ecosystem

China’s Consumption Driven Growth Path

International Development,

The Sustainability of China's Recovery from the Global Recession

China faces major challenges in sustaining its economic growth in a period of weak global recovery, particularly in Europe. In 2009 China's net exports of goods and services dropped precipitously, resulting in a substantial drag on economic growth. To overcome this drag China launched a massive stimulus program, financed largely with bank credit. While it is now widely understood that China was the first globally significant economy to begin to recover from the crisis, critics nonetheless increasingly charge that the stimulus program has substantial flaws and that China's early economic recovery cannot be sustained. One prominent critic has gone so far as to suggest that the stimulus has created a debt-fueled bubble that will collapse, causing China's growth to plunge to only 2 percent. Nicholas Lardy suggests these criticisms are exaggerated. Contrary to repeated criticisms, this stimulus had a substantial consumption component and focused on investment in infrastructure rather than expanding capacity in traditional industries such as steel. But the stimulus did come at a cost insofar as it led to a substantial increase in the borrowing of local investment companies, which local governments will have to ultimately repay, but the infrastructure provided through these companies likely will contribute to China's sustained economic growth and thus to increasing government tax revenues as well. The authorities recognize flooding the economy with more credit is not the way forward and that they will have to take strong additional policy initiatives to sustain economic growth. These include raising the prices of inputs such as water, electricity, and other resource products as well as introducing realistic environmental taxes and fees. These reforms, as well as a more flexible exchange rate, would reduce the distortions that for much of the past decade have favored industrial growth and exports over services and consumption and would contribute to sustaining China's impressive long-term economic growth.