Amino acid composition of proteins reduces deleterious impact of mutations

The evolutionary origin of amino acid occurrence frequencies in proteins (composition) is not yet fully understood. We suggest that protein composition works alongside the genetic code to minimize impact of mutations on protein structure. First, we propose a novel method for estimating thermodynamic stability of proteins whose sequence is constrained to a fixed composition. Second, we quantify the average deleterious impact of substituting one amino acid with another. Natural proteome compositions are special in at least two ways: 1) Natural compositions do not generate more stable proteins than the average random composition, however, they result in proteins that are less susceptible to damage from mutations. 2) Natural proteome compositions that result in more stable proteins (i.e. those of thermophiles) are also tuned to have a higher tolerance for mutations. This is consistent with the observation that environmental factors selecting for more stable proteins also enhance the deleterious impact of mutations

Quantum Collapse and the Second Law of Thermodynamics

A heat engine undergoes a cyclic operation while in equilibrium with the net result of conversion of heat into work. Quantum effects such as superposition of states can improve an engine's efficiency by breaking detailed balance, but this improvement comes at a cost due to excess entropy generated from collapse of superpositions on measurement. We quantify these competing facets for a quantum ratchet comprised of an ensemble of pairs of interacting two-level atoms. We suggest that the measurement postulate of quantum mechanics is intricately connected to the second law of thermodynamics. More precisely, if quantum collapse is not inherently random, then the second law of thermodynamics can be violated. Our results challenge the conventional approach of simply quantifying quantum correlations as a thermodynamic work deficit.Comment: 11 pages, 2 figure

The Effect Of A Stability And Strengthening Program On The Oswestry Disability Index In A 14-Year-Old Patient With Spondylolisthesis: A Case Report

Background and Purpose: Spondylolisthesis is a condition that describes the anterior translation of the cephalad vertebral segment of the skeletal spine relative to the caudal segment. This condition comes about by forces of gravity acting through the lordotic curve of the lumbar spine. Repetitive extension movements and weakened stabilizing muscles of the trunk like the abdominals and the gluteals may also play a role in contributing to spondylolisthesis. There is an increase in incidence rate of spondylolisthesis in adolescents who participate in sports involving repetitive extension motions. The purpose of this study is to examine the effectiveness of physical therapy management aimed at stability and strengthening for an adolescent with spondylolisthesis. Case Description: The patient was a 14-year-old female who was referred to an outpatient orthopedic physical therapy clinic diagnosed with spondylolisthesis at the level of L5 with imaging. Upon evaluation, the patient demonstrated hyperflexibility, joint hypomobility, weakness and instability. Treatments included gluteals and abdominal strengthening and stabilization. The Oswestry Disability Index (ODI) was used to quantify impairment and to measure improvement over the episode of care. Outcomes: During the initial evaluation, the patient reported a Numeric Pain Rating Scale (NPRS) of 6/10 at worse, an ODI score of 62% and a Manual Muscle Testing (MMT) grade of 2/5, 3/5 and 3/5 for transverse abdominus, hip extension and hip abduction, respectively. At the four-week point the patient reported a NPRS of 4/10 at worse, an ODI score of 20% and a MMT of 2+/5 for transverse abdominus with no change for hip extension and hip abduction. Results improved further during discharge with a reported 2/10 on the NPRS, a 7% on the ODI and MMT improvements to 3/5, 4/5 and 4/5 for transverse abdominus, hip extension and hip abduction, respectively. Discussion: Abdominal stabilization and gluteal strengthening seem to have a positive effect in reducing both pain and ODI score of a fourteen-year-old dancer with low back pain caused by spondylolisthesis

Essays on asset pricing and financial regulation

I show that when the banking sector’s assets comprise large excess reserves and loans, jointly determined capital regulation and interest-on-excess-reserves (IOER) policies provide welfare gains. In general equilibrium, falling IOER is associated with a proportional fall in deposit rate only when IOER is above the zero bound. This leads to a faster fall in the bank’s interest expenses than its interest incomes. Given any lending level, lower net interest expenses enhance bank solvency. Nonetheless, the risk-weighted capital regulation remains unchanged and hence becomes socially costly. I show that jointly determined policies achieve welfare gains by loosening the capital requirement and lowering IOER to expand the credit flow, while bank failure likelihood remains constant. Conversely, lowering IOER below the zero bound is associated with a nonresponsive deposit rate that leads to growing net interest expenses and worsening bank solvency. In that case, I show that a stricter capital constraint together with a lower IOER provide social value. The aftermath of the financial crisis inherited heightened economic uncertainty and low productivity. These features prompted the banking sectors across the developed economies to rely heavily on excess reserves offered by the central banks despite the negative nominal IOER policy rate. Nonetheless, the negative relationship between the overall interest expenses of the banking sector with the IOER around the zero lower bound further exacerbates the over-reliance on excess reserves particularly when rates are negative. Financial regulator faces a trade-off between the costly failure of an under-capitalized banking system and costs generated by interconnections between interest expenses on oversized excess reserves and government guarantees to depositors. I show that first, the risk-weighted optimal capital regulation exhibits a negative correlation with the IOER policy rate, and second present a socially optimal financial regulation that balances the social gains of negative IOER rate, generated by reduced over-reliance on idle reserves, against its social costs, generated by the increased default likelihood of the banking institutions.Open Acces

Site selection criteria for resort development and a case study in northern New England

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1990.Includes bibliographical references (leaves 167-170).by Hormoz Lashkari and Christopher Voutsinas.M.S

Accelerating Evolution Through Gene Masking and Distributed Search

In building practical applications of evolutionary computation (EC), two optimizations are essential. First, the parameters of the search method need to be tuned to the domain in order to balance exploration and exploitation effectively. Second, the search method needs to be distributed to take advantage of parallel computing resources. This paper presents BLADE (BLAnket Distributed Evolution) as an approach to achieving both goals simultaneously. BLADE uses blankets (i.e., masks on the genetic representation) to tune the evolutionary operators during the search, and implements the search through hub-and-spoke distribution. In the paper, (1) the blanket method is formalized for the (1 + 1)EA case as a Markov chain process. Its effectiveness is then demonstrated by analyzing dominant and subdominant eigenvalues of stochastic matrices, suggesting a generalizable theory; (2) the fitness-level theory is used to analyze the distribution method; and (3) these insights are verified experimentally on three benchmark problems, showing that both blankets and distribution lead to accelerated evolution. Moreover, a surprising synergy emerges between them: When combined with distribution, the blanket approach achieves more than $n$-fold speedup with $n$ clients in some cases. The work thus highlights the importance and potential of optimizing evolutionary computation in practical applications

Embracing Sustainability: A Survey of US Small and Medium-Sized Enterprises

Studies on sustainability strategies of small and medium-sized enterprises (SMEs) have primarily been done on European firms and less on those in Asia and Latin America. Fewer research is done on US SMEs to show the factors that have motivated or hindered their embracing sustainability. We bridged this gap by surveying over 600 New York SMEs. Results indicated that owners’/managers’ values, awareness, and sustainability education emerged as the key factors influencing their adoption of sustainability. Government regulations or financial incentives to coerce or encourage sustainability played a lesser role. Significant barriers were the cost of implementation and the firm’s limited resources