The Effects of Horizontal Gene Transfer on the Evolution of Land Plants

This study sought to understand how horizontal gene transfer (HGT) has affected the evolution of land plants. Land plants evolved from charophyte green algae. A list of candidate genes derived from HGT was generated from the genome of the charophyte green alga Chlorokybus atmophyticus and were subjected to detailed phylogenetic analyses to investigate their evolutionary origin. The flowering plant Arabidopsis thaliana was used as a reference organism to understand the functions of the investigated genes, which in turn were used to assess the contribution of acquired genes to the evolution and adaptation of plants. I performed a detailed investigation on three acquired genes, including Chrsp45S09062 in the cupredoxin superfamily that encodes a multicopper oxidase protein, Chrsp52S06587 that encodes a calcium-dependent phosphotriesterase superfamily protein, and Chrsp22S08802 that encodes a protein with histidine kinase 1 activity. BLASTP searches were performed against the NCBI non-redundant protein sequence database using the HGT candidate genes from C. atmophyticus. Identified homologs were sampled for each candidate gene from representative groups of both prokaryotes and eukaryotes and then input into the computer program MEGA to perform a multiple sequence alignment (MSA). A phylogenetic tree was generated for each gene using MEGA and the resulting MSA. The phylogenetic trees generated were analyzed to identify true cases of HGT, and biochemical functions and related biological processes were further researched on each acquired gene to determine the effects of HGT on plant evolution. In the evolution of plants, the expected impact of HGT is a mechanism that aids in the exchange of genetic information to benefit the adaptation of land plants to their environment

An asynchronous direct solver for banded linear systems

Banded linear systems occur frequently in mathematics and physics. However, direct solvers for large systems cannot be performed in parallel without communication. The aim of this paper is to develop a general asymmetric banded solver with a direct approach that scales across many processors efficiently. The key mechanism behind this is that reduction to a row-echelon form is not required by the solver. The method requires more floating point calculations than a standard solver such as LU decomposition, but by leveraging multiple processors the overall solution time is reduced. We present a solver using a superposition approach that decomposes the original linear system into q subsystems, where q is the number of superdiagonals. These methods show optimal computational cost when q processors are available because each system can be solved in parallel asynchronously. This is followed by a q×q dense constraint matrix problem that is solved before a final vectorized superposition is performed. Reduction to row echelon form is not required by the solver, and hence the method avoids fill-in. The algorithm is first developed for tridiagonal systems followed by an extension to arbitrary banded systems. Accuracy and performance is compared with existing solvers and software is provided in the supplementary material

Water Walking as a New Mode of Free Surface Skipping

Deformable elastomeric spheres are evaluated experimentally as they skip multiple times over a lake surface. Some spheres are embedded with small inertial measurement units to measure the acceleration experienced during water surface impact. A model for multiple impact events shows good agreement between measured acceleration, number of skipping events and distanced traveled. The experiment reveals a new mode of skipping, “water walking”, which is observed for relatively soft spheres impacting at low impact angles. The mode occurs when the sphere gains significant angular velocity over the first several impacts, causing the sphere to maintain a deformed, oblong shape. The behavior is characterized by the sphere moving nearly parallel to the water surface with the major axis tips dipping below the water surface with each rotation while the shorter sides pass just above, giving the impression that the sphere is walking across the water surface

Patient Perceptions of Physical and Emotional Discomfort Related to Urodynamic Testing: A Questionnaire-based Study in Men and Women With and Without Neurologic Conditions

ObjectiveTo determine predictors of physical and emotional discomfort associated with urodynamic testing in men and women both with and without neurologic conditions.MethodsAn anonymous questionnaire-based study was completed by patients immediately after undergoing fluoroscopic urodynamic testing. Participants were asked questions pertaining to their perceptions of physical and emotional discomfort related to the study, their urologic and general health history, and demographics. Logistic regression was performed to determine predictors of physical and emotional discomfort.ResultsA total of 314 patients completed the questionnaire representing a response rate of 60%. Half of the respondents (50.7%) felt that the examination was neither physically nor emotionally uncomfortable, whereas 29.0% and 12.4% of respondents felt that the physical and emotional components of the examination were most uncomfortable, respectively. Placement of the urethral catheter was the most commonly reported component of physical discomfort (42.9%), whereas anxiety (27.7%) was the most commonly reported component of emotional discomfort. Presence of a neurologic problem (odds ratio, 0.273; 95% confidence interval, 0.121-0.617) and older age (odds ratio, 0.585; 95% confidence interval, 0.405-0.847) were factors associated with less physical discomfort. There were no significant predictors of emotional discomfort based on our model.ConclusionUrodynamic studies were well tolerated regardless of gender. Presence of a neurologic condition and older age were predictors of less physical discomfort. These findings are useful in counseling patients regarding what to expect when having urodynamic procedures

Patient Perceptions of Physical and Emotional Discomfort Related to Urodynamic Testing: A Questionnaire-based Study in Men and Women With and Without Neurologic Conditions

OBJECTIVES: To determine predictors of physical and emotional discomfort associated with urodynamic testing in men and women both with and without neurologic conditions. METHODS: An anonymous questionnaire-based study completed by patients immediately after undergoing fluoroscopic urodynamic testing. Participants were asked questions pertaining to their perceptions of physical and emotional discomfort related to the study, their urologic and general health history, and demographics. Logistic regression was performed to determine predictors of physical and emotional discomfort. RESULTS: A total of 314 patients completed the questionnaire representing a response rate of 60%. Half of the respondents (50.7%) felt that the exam was neither physically nor emotionally uncomfortable, while 29.0% and 12.4% of respondents felt that the physical and emotional components of the exam were most uncomfortable, respectively. Placement of the urethral catheter was the most commonly reported component of physical discomfort (42.9%), while anxiety (27.7%) was the most commonly reported component of emotional discomfort. Having a neurologic problem (OR 0.273; 95% CI 0.121, 0.617) and older age (OR 0.585; 95% CI 0.405, 0.847) were factors associated with less physical discomfort. There were no significant predictors of emotional discomfort based on our model. CONCLUSIONS: Urodynamic studies were well tolerated regardless of gender. Having a neurologic condition and older age were predictors of less physical discomfort. These findings are useful in counseling patients regarding what to expect when having urodynamic procedures