Zeta diversity differentiates factors driving community assembly of rare and common ectomycorrhizal fungi

A fundamental goal in community ecology is to understand what factors drive community assembly processes. The factors affecting ectomycorrhizal fungal communities are unknown in many regions, particularly in the southern hemisphere. We investigate community assembly using ITS2 metabarcoding of ectomycorrhizal fungi sampled from 3943 hyphal ingrowth bags buried in 81 Nothofagus forests across New Zealand's South Island. By applying zeta diversity analysis and multisite generalized dissimilarity modelling (MS-GDM) we quantify the effects of 43 biotic and environmental variables on community turnover. Unlike traditional beta diversity analyses that are heavily influenced by rare species, the zeta diversity framework differentiates between factors driving turnover of rare and common species, providing a more complete picture of community dynamics. We found that community assembly was dominated by deterministic rather than stochastic processes and identified ecological factors affecting all taxa, as well as others that were specifically important to rare or common taxa. Soil variables were important drivers of turnover for all species, whereas ground cover variables, forest patch size, precipitation and host tree identity had greater effects on rarer species, and tree size and temperature effects were specific to more common species. Interestingly, the effect of temperature on common species is in line with recent evidence from other Kingdoms, pointing to possible generality, and highlighting the importance of considering common species. Applying these methods to fungi has allowed us to identify the distinct ecological processes that structure rare and common taxa during community assembly. This has important implications for understanding the functional effects of community responses to environmental change.

Innovative pattern reversal displays for visual electrophysiological studies

Pattern Reversal (PR) stimulation is a frequently used tool in the evaluation of the visual pathway. The PR stimulus consists of a field of black and white segments (usually checks or bars) of constant luminance, which change phase (black to white and white to black) at a given reversal rate. The Pattern Electroretinogram (PERG) is a biological potential that is evoked from the retina upon viewing PR display. Likewise, the Pattern Visual Evoked Potential (PVEP) is a biological potential recorded from the occipital cortex when viewing a PR display. Typically, PR stimuli are presented on a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD) monitor. This paper presents three modalities to generate pattern reversal stimuli. The three methods are as follows: a display consisting of array of Light Emitting Diodes (LEDs), a display comprised of two miniature projectors, and a display utilizing a modified LCD display in conjunction with a variable polarizer. The proposed stimulators allow for the recording of PERG and PVEP waveforms at much higher rates than are capable with conventional stimulators. Additionally, all three of the alternative PR displays will be able to take advantage of advanced analysis techniques, such as the recently developed Continuous Loop Averaging Deconvolution (CLAD) algorithm.

Interactive neuromonitoring methods of cochlea and auditory nerve during induced hypoxia and nerve manipulation

Methods and instrumentation were developed to monitor cochlea and auditory function during surgery. The system allows real time assessment of the cochlear function during auditory nerve manipulation. A specially designed optic probe, placed on the round window (RW) niche, enables simultaneous acquisition of cochlear blood flow (CBF) and electrocochleogram (ECochG). We developed the acquisition paradigms, signal processing methods and implement them in a computational platform. The neuromonitoring system performs an automatic extraction and analysis of cochlear microphonics (CM), compound action potentials (CAP) and sura mating potential (SP). The system uses envelope detection filters to detect the amplitude of the CM. The CAP signal is processed with zero phase shift spectral filters, tuned to enhance the action potential onset, which is sometimes embedded within the sura mating potential. An automatic peak detection and tracking algorithm is then applied to extract latency and amplitude of CAPs. Long-term assessment of the monitoring system was performed during experimental animal surgeries. The system allowed detailed study of the dynamics of CM, CAP and CBF during nerve manipulation and compression.

Time-frequency digital filtering based on an invertible wavelet transform: an application to evoked potentials

This paper presents a method to analyze and filter digital signals of finite duration by means of a time-frequency representation. This is done by defining a purely invertible discrete transform, representing a signal either in the time or in the time-frequency domain, as simply as possible with the conventional discrete Fourier transform between the time and the frequency domains. The wavelet concept has been used to build this transform. To get a correct invertibility of this procedure, we have proposed orthogonal and periodic basic discrete wavelets. The properties of such a transform are described, and examples on brain-evoked potential signals are given to illustrate the time-frequency filtering possibilities.

Irradiation of carcinoma of the esophagus containing a tracheoesophageal fistula

BACKGROUND

For patients with locally advanced esophageal carcinoma, tracheal involvement is common, and the formation of a tracheoesophageal fistula is a frequent complication of the disease, with or without treatment. However, the presence of a tracheoesophageal fistula has historically been considered a relative contraindication to radiation therapy. Therefore, we are presenting a case report whereby irradiation was continued despite the presence of such a fistula.

METHODS

A 60-year-old white man diagnosed with Stage III, T4N0M0, moderately well-differentiated invasive squamous cell carcinoma of the esophagus was initially treated with four courses of chemotherapy (5-fluorouracil and cisplatin) and had an excellent tumor response. He was then referred for consolidative radiation therapy (XRT). At 600 cGy, he had symptoms consistent with a tracheoesophageal fistula (TEF), which was documented by barium swallow at 3000 cGy. Radiation treatments were continued, but at a reduced fraction size that was gradually increased over several days.

RESULTS

Upon completion of the radiation therapy, the TEF persisted but had completely disappeared 2 months post-XRT. However, at 4 months post-XRT, the fistula recurred due to tumor recurrence. At 6 months post-XRT, he died with metastatic disease, 16 months after initial diagnosis and 8.5 months after the first TEF occurred.

CONCLUSIONS

The presence of a TEF may not be an absolute contraindication to radiation therapy. Radiation therapy may be initiated or continued in the presence of a TEF, and eventual resolution of the fistula may occur. Recurrence of a healed TEF may indicate recurrence of a tumor.

Irradiation of carcinoma of the esophagus containing a tracheoesophageal fistula

BACKGROUND

For patients with locally advanced esophageal carcinoma, tracheal involvement is common, and the formation of a tracheoesophageal fistula is a frequent complication of the disease, with or without treatment. However, the presence of a tracheoesophageal fistula has historically been considered a relative contraindication to radiation therapy. Therefore, we are presenting a case report whereby irradiation was continued despite the presence of such a fistula.

METHODS

A 60-year-old white man diagnosed with Stage III, T4N0M0, moderately well-differentiated invasive squamous cell carcinoma of the esophagus was initially treated with four courses of chemotherapy (5-fluorouracil and cisplatin) and had an excellent tumor response. He was then referred for consolidative radiation therapy (XRT). At 600 cGy, he had symptoms consistent with a tracheoesophageal fistula (TEF), which was documented by barium swallow at 3000 cGy. Radiation treatments were continued, but at a reduced fraction size that was gradually increased over several days.

RESULTS

Upon completion of the radiation therapy, the TEF persisted but had completely disappeared 2 months post-XRT. However, at 4 months post-XRT, the fistula recurred due to tumor recurrence. At 6 months post-XRT, he died with metastatic disease, 16 months after initial diagnosis and 8.5 months after the first TEF occurred.

CONCLUSIONS

The presence of a TEF may not be an absolute contraindication to radiation therapy. Radiation therapy may be initiated or continued in the presence of a TEF, and eventual resolution of the fistula may occur. Recurrence of a healed TEF may indicate recurrence of a tumor.

Treatment of hepatic metastases with a combination of hepatic artery infusion chemotherapy and external radiotherapy

Systemic chemotherapy has given good results when compared with that of patients who received no chemotherapy. When resection was performed, the results are slightly better. The group of patients who underwent combined therapy, using infusion chemotherapy, radiation and systemic chemotherapy, had the best results. It appears that infusion chemotherapy and radiotherapy can improve the palliation available for patients with metastases in the liver from carcinoma of the colon and rectum and warrants further investigation.

Factors that modify the radio-response of cancer of the nasopharynx

A study of 152 cases of carcinoma of the nasopharynx was carried out for evaluation of various features of the tumors. Survival is greatest in middle aged patients and poorest in patients under 20 years of age. Patients who presented with lymph node involvement had a better survival rate than those without, and those with undifferentiated tumors survived longer, although tumors in this group metastasized earlier. Those tumors which arose on the postero-superior wall of the nasopharynx were associated with a lower cure rate than those situated elsewhere. Spread to adjacent tissues diminished the cure rate, but the rate fell particularly low if there was spread to bone or to the central nervous system. If no neck lymph nodes were involved, patients with undifferentiated and well-differentiated lesions fared equally well, but if there was involvement of the neck lymph nodes, those with undifferentiated primary lesions obtained a better cure rate. The influence of the type of local spread, the presence of distant metastasis, and survival in relation to the histological and clinical grading of the tumor were also evaluated.