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We used an extensive multispecies dataset to examine how C and N stable isotope ratios (δ13C and δ15N) of aquatic consumers varied with body size in populations of northern lakes. Ontogenetic variation in tissue δ13C and δ15N was evident in a diversity of aquatic consumers. Relationships with body size tended to be stronger and more consistently positive for δ15N, and more variable in nature for δ13C. Among-population variation in ontogenetic slopes was greater for δ13C than for δ15N for most biota examined. Relationships between δ13C and δ15N and body size were still significant even after accounting for variation owing to tissue C:N and body condition. Ontogenetic variation was more strongly linked to age than body size in some fishes, particularly for δ15N, but age effects, inferred from growth rate, also accounted for variation in δ13C and δ15N beyond body size effects; δ13C tended to be positively related and δ15N tended to be negatively related to growth rate. There was only limited evidence of concordance in ontogenetic slopes between co-habiting pairs of species, suggesting that the factors driving ontogenetic variation in stable isotope ratios may be largely species- or population-specific. However, ontogenetic slopes of individual taxa were related to various lake habitat features representing climate, ecosystem size, and water clarity. The proportion of isotopic niche space attributable to ontogenetic variation can be substantial and this has implications for applying and interpreting isotopic niche metrics. Our study provides the broadest and most comprehensive analysis of ontogenetic variation in isotopic compositions of freshwater consumers to date and our results underscore the need to account for this variation in the analysis of freshwater food webs. [ABSTRACT FROM AUTHOR]

We present a method for precise monitoring of the loop gain of transition edge sensors (TES) under electrothermal feedback. The measurement is implemented on the ICE DfMux electronics and operates simultaneously with Digital Active Nulling (DAN). It uses one additional bias sinusoid per TES and does not require any additional readout channels. The loop gain monitor is being implemented on the Simons Array and is an integral part of the baseline calibration strategy for the upcoming LiteBIRD satellite. [ABSTRACT FROM AUTHOR]

The Summertime Line Intensity Mapper (SLIM) is a mm-wave line-intensity mapping (mm-LIM) experiment for the South Pole Telescope (SPT). The goal of SPT-SLIM is to serve as a technical and scientific pathfinder for the demonstration of the suitability and in-field performance of multi-pixel superconducting filterbank spectrometers for future mm-LIM experiments. Scheduled to deploy in the 2023-24 austral summer, the SPT-SLIM focal plane will include 18 dual-polarisation pixels, each coupled to an R = λ / Δ λ = 300 thin-film microstrip filterbank spectrometer that spans the 2 mm atmospheric window (120–180 GHz). Each individual spectral channel feeds a microstrip-coupled lumped-element kinetic inductance detector, which provides the highly multiplexed readout for the 10k detectors needed for SPT-SLIM. Here, we present an overview of the preliminary design of key aspects of the SPT-SLIM focal plane array, a description of the detector architecture and predicted performance, and initial test results that will be used to inform the final design of the SPT-SLIM spectrometer array. [ABSTRACT FROM AUTHOR]

The South Pole Telescope Summertime Line Intensity Mapper (SPT-SLIM) is a pathfinder experiment that will demonstrate the use of on-chip filter-bank spectrometers for mm-wave line intensity mapping. The SPT-SLIM focal plane consists of 18 dual-polarization filter-bank spectrometers covering 120–180 GHz with resolving power of 300, coupled to aluminum kinetic inductance detectors. A compact cryostat holds the detectors at 100 mK. SPT-SLIM will be deployed to the 10-m South Pole Telescope for observations during the 2023–2024 austral summer without removing the primary receiver. We discuss the overall instrument design, expected detector performance, and sensitivity to the carbon monoxide line signal at 0.5 < z < 2 . The technology and observational techniques demonstrated by SPT-SLIM will enable next-generation line intensity mapping experiments that constrain cosmology beyond the redshift reach of galaxy surveys. [ABSTRACT FROM AUTHOR]

Digital Frequency-Domain Multiplexing (DfMux) is a technique that uses MHz superconducting resonators and Superconducting Quantum Interference Device (SQUID) arrays to read out sets of transition edge sensors. DfMux has been used by several Cosmic Microwave Background experiments, including most recently POLARBEAR-2 and SPT-3 G with multiplexing factors as high as 68, and is the baseline readout technology for the planned satellite mission LiteBIRD. Here, we present recent work focused on improving DfMux readout noise, reducing parasitic impedance, and improving sensor operation. We have achieved a substantial reduction in stray impedance by integrating the sensors, resonators, and SQUID array onto a single-carrier board operated at 250 mK. This also drastically simplifies the packaging of the cryogenic components and leads to better-controlled crosstalk. We demonstrate a low readout noise level of 8.6 pA / Hz 1 1 / 2 , which was made possible by operating the SQUID array at a reduced temperature and with a low dynamic impedance. This is a factor of two improvement compared to the achieved readout noise level in currently operating Cosmic Microwave Background experiments using DfMux and represents a critical step toward maturation of the technology for the next generation of instruments. [ABSTRACT FROM AUTHOR]

Frequency-domain multiplexing (fMUX) is a mature readout scheme for transition edge sensor (TES) detectors in the millimetre and sub-millimetre bands. It is implemented at MHz carrier frequencies for the South Pole Telescope, POLARBEAR, and Simons Array and is planned for deployment on the LiteBIRD space polarimeter. The existing implementations couple to the detectors with low-noise, low-input-impedance superconducting quantum interference device (SQUID) transimpedance amplifiers and rely on complex arrangements to achieve sufficient linearity and dynamic range. We introduce a new cryogenic amplification scheme that couples the multiplexed TES devices to a traditional, high-linearity, high-dynamic-range, field-effect transistor amplifier using a novel high-turns-ratio, wide-band cryogenic transformer. We characterize the bandwidth, transimpedance, input impedance, and system noise of the transformer-coupled fMUX system to demonstrate that it is a promising candidate for MHz frequency-domain multiplexing without the use of SQUIDs. For the initial prototype, we demonstrate a bandwidth of 1.5–6 MHz, transimpedance of 267 ± 2 Ω , input impedance of 0.2 Ω , and system noise 16 ± 3 pA / Hz . We also present an optimized design which will have amplifier noise contributions of approximately 5 pA / Hz , comparable to the SQUID contribution in the existing systems. [ABSTRACT FROM AUTHOR]

Frequency-domain multiplexing is a readout technique for transition-edge sensor bolometer arrays used on modern cosmic microwave background experiments, including the SPT-3G receiver. Here, we present design details and performance measurements for a low-parasitic frequency-domain multiplexing readout. Reducing the parasitic impedance of the connections between cryogenic components provides a path to improve both the crosstalk and noise performance of the readout. Reduced crosstalk will in turn allow higher-multiplexing factors. We have demonstrated a factor of two improvement in parasitic resistance compared to SPT-3G hardware. Reduced parasitics also permits operation of lower-resistance bolometers optimized for improved readout noise performance. We demonstrate that a module in the prototype system has comparable readout noise performance to an SPT-3G module when operated with dark TES bolometers in the laboratory. [ABSTRACT FROM AUTHOR]

A heat treatment methodology is described for obtaining ultra-high strength (> 1700 MPa) and increased − 40 °C toughness (> 45 J/cm2) in a steel. Thermodynamic approach to design heat treatments is demonstrated and utilized to produce refinement of the prior austenite grain size leading to superior properties. The cleavage energy was shown to correlate to both prior austenite grain size, according to an inverse root relationship, as well as the density of high-angle martensite lath boundaries. [ABSTRACT FROM AUTHOR]

Background: Cisplatin-based neoadjuvant chemotherapy (NAC) for muscle invasive bladder cancer improves all-cause and cancer specific survival. We aimed to evaluate whether the detection of carcinoma in situ (CIS) at the time of initial transurethral resection of bladder tumor (TURBT) has an oncological impact on the response to NAC prior to radical cystectomy.Patients and methods: Patients were identified retrospectively from 19 centers who received at least three cycles of NAC or induction chemotherapy for cT2-T4aN0-3M0 urothelial carcinoma of the bladder followed by radical cystectomy between 2000 and 2013. The primary and secondary outcomes were pathological response and overall survival, respectively. Multivariable analysis was performed to determine the independent predictive value of CIS on these outcomes.Results: Of 1213 patients included in the analysis, 21.8% had concomitant CIS. Baseline clinical and pathologic characteristics of the 'CIS' versus 'no-CIS' groups were similar. The pathological response did not differ between the two arms when response was defined as pT0N0 (17.9% with CIS vs 21.9% without CIS; p = 0.16) which may indicate that patients with CIS may be less sensitive to NAC or ≤ pT1N0 (42.8% with CIS vs 37.8% without CIS; p = 0.15). On Cox regression model for overall survival for the cN0 cohort, the presence of CIS was not associated with survival (HR 0.86 (95% CI 0.63-1.18; p = 0.35). The presence of LVI (HR 1.41, 95% CI 1.01-1.96; p = 0.04), hydronephrosis (HR 1.63, 95% CI 1.23-2.16; p = 0.001) and use of chemotherapy other than ddMVAC (HR 0.57, 95% CI 0.34-0.94; p = 0.03) were associated with shorter overall survival. For the whole cohort, the presence of CIS was also not associated with survival (HR 1.05 (95% CI 0.82-1.35; p = 0.70).Conclusion: In this multicenter, real-world cohort, CIS status at TURBT did not affect pathologic response to neoadjuvant or induction chemotherapy. This study is limited by its retrospective nature as well as variability in chemotherapy regimens and surveillance regimens. [ABSTRACT FROM AUTHOR]

The Simons Array (SA) is a cosmic microwave background (CMB) polarization experiment comprised of three telescopes that will observe the CMB at 90, 150, 220, and 270 GHz with more than 22,000 Transition Edge Sensor (TES) bolometers. The cryogenic receivers inside each telescope are named POLARBEAR-2a, POLARBEAR-2b, and POLARBEAR-2c (PB-2a, PB-2b, and PB-2c, respectively). To allow for the large number of detectors, SA uses frequency-division multiplexing with multiplexing factor of 40. We describe the process developed to assemble the readout circuit repeatably for SA. After assembly, we characterize the readout circuit and TESs at cryogenic temperatures in a condition of negligible incident optical power. Impedances in the readout circuit bias our estimates of TES parameters, and we describe a method to account for this. [ABSTRACT FROM AUTHOR]

CD103+CD11b+ dendritic cells (DCs) are unique to the intestine, but the factors governing their differentiation are unclear. Here we show that transforming growth factor receptor 1 (TGFβR1) has an indispensable, cell intrinsic role in the development of these cells. Deletion of Tgfbr1 results in markedly fewer intestinal CD103+CD11b+ DCs and a reciprocal increase in the CD103-CD11b+ dendritic cell subset. Transcriptional profiling identifies markers that define the CD103+CD11b+ DC lineage, including CD101, TREM1 and Siglec-F, and shows that the absence of CD103+CD11b+ DCs in CD11c-Cre.Tgfbr1 fl/fl mice reflects defective differentiation from CD103-CD11b+ intermediaries, rather than an isolated loss of CD103 expression. The defect in CD103+CD11b+ DCs is accompanied by reduced generation of antigen-specific, inducible FoxP3+ regulatory T cells in vitro and in vivo, and by reduced numbers of endogenous Th17 cells in the intestinal mucosa. Thus, TGFβR1-mediated signalling may explain the tissue-specific development of these unique DCs.Developmental cues for the different dendritic cell (DC) subsets in the intestine are yet to be defined. Here the authors show that TGFβR1 signalling is needed for development of CD103+CD11b+ intestinal DCs from CD103-CD11b+ cells and that they contribute to the generation of Th17 and regulatory T cells. [ABSTRACT FROM AUTHOR]

The readout of transition-edge sensor (TES) bolometers with a large multiplexing factor is key for the next generation cosmic microwave background (CMB) experiment, Polarbear-2 (Suzuki in J Low Temp Phys 176:719, ), having 7588 TES bolometers. To enable the large arrays, we have been developing a readout system with a multiplexing factor of 40 in the frequency domain. Extending that architecture to 40 bolometers requires an increase in the bandwidth of the SQUID electronics, above 4 MHz. This paper focuses on cryogenic readout and shows how it affects cross talk and the responsivity of the TES bolometers. A series resistance, such as equivalent series resistance of capacitors for LC filters, leads to non-linear response of the bolometers. A wiring inductance modulates a voltage across the bolometers and causes cross talk. They should be controlled well to reduce systematic errors in CMB observations. We have been developing a cryogenic readout with a low series impedance and have tuned bolometers in the middle of their transition at a high frequency ( $$>$$ 3 MHz). [ABSTRACT FROM AUTHOR]

Purpose: To determine whether focal peripheral zone enhancement on routine venous-phase CT is predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer. Materials and methods: IRB approval was obtained and informed consent waived for this HIPAA-compliant retrospective study. Forty-three patients with higher-grade prostate cancer (≥Gleason 4 + 3) and 96 with histology-confirmed lower-grade (≤Gleason 3 + 4 [ n = 47]) or absent ( n = 49) prostate cancer imaged with venous-phase CT comprised the study population. CT images were reviewed by ten blinded radiologists (5 attendings, 5 residents) who scored peripheral zone enhancement on a scale of 1 (benign) to 5 (malignant). Mass-like peripheral zone enhancement was considered malignant. Likelihood ratios (LR) and specificities were calculated. Multivariate conditional logistic regression analyses were conducted. Results: Scores of '5' were strongly predictive of higher-grade prostate cancer (pooled LR+ 9.6 [95% CI 5.8-15.8]) with rare false positives (pooled specificity: 0.98 [942/960, 95% CI 0.98-0.99]; all 10 readers had specificity ≥95%). Attending scores of '5' were more predictive than resident scores of '5' (LR+: 14.7 [95% CI 5.8-37.2] vs. 7.6 [95% CI 4.2-13.7]) with similar specificity (0.99 [475/480, 95% CI 0.98-1.00] vs. 0.97 [467/480, 95% CI 0.96-0.99]). Significant predictors of an assigned score of '5' included presence of a peripheral zone mass ( p < 0.0001), larger size ( p < 0.0001), and less reader experience ( p = 0.0008). Significant predictors of higher-grade prostate cancer included presence of a peripheral zone mass ( p = 0.0002) and larger size ( p < 0.0001). Conclusion: Focal mass-like peripheral zone enhancement on routine venous-phase CT is specific and predictive of higher-grade (Gleason 4 + 3 and higher) prostate cancer. [ABSTRACT FROM AUTHOR]

A multiphysics computational model has been developed for the conventional Gas Metal Arc Welding (GMAW) joining process and used to analyze butt-welding of MIL A46100, a prototypical high-hardness armor martensitic steel. The model consists of five distinct modules, each covering a specific aspect of the GMAW process, i.e., (a) dynamics of welding-gun behavior; (b) heat transfer from the electric arc and mass transfer from the electrode to the weld; (c) development of thermal and mechanical fields during the GMAW process; (d) the associated evolution and spatial distribution of the material microstructure throughout the weld region; and (e) the final spatial distribution of the as-welded material properties. To make the newly developed GMAW process model applicable to MIL A46100, the basic physical-metallurgy concepts and principles for this material have to be investigated and properly accounted for/modeled. The newly developed GMAW process model enables establishment of the relationship between the GMAW process parameters (e.g., open circuit voltage, welding current, electrode diameter, electrode-tip/weld distance, filler-metal feed speed, and gun travel speed), workpiece material chemistry, and the spatial distribution of as-welded material microstructure and properties. The predictions of the present GMAW model pertaining to the spatial distribution of the material microstructure and properties within the MIL A46100 weld region are found to be consistent with general expectations and prior observations. [ABSTRACT FROM AUTHOR]

Swim bladder extensions and hearing ability were examined in the temperate reef fish Polyprion oxygeneios (hapuka). Using the auditory evoked potential (AEP) technique, hearing thresholds were determined in four age-classes of hapuka, from larvae to juveniles. The youngest age-class had poor hearing abilities, with lowest thresholds of 132 dB re 1 μPa, and a narrow auditory bandwidth (100-800 Hz). Hearing ability improved significantly throughout the remainder of their first year, including decreases in thresholds of up to 27 dB, and an increase in auditory bandwidth (up to 1,000 Hz). Magnetic resonance imaging (MRI) was used to investigate structural mechanisms that may account for this ontogenetic improvement in hearing. These showed rostral extensions of the swim bladder developing early in the juvenile stage, and extending with increasing age closer to the otic capsule. It is suggested that this indirect connection between the swim bladder and the otic capsule could impart pressure sensitivity closer to the inner ear, accounting for the increase in sensitivity seen during development, although further investigation of older fish is required for conclusive evidence. The improvement in hearing ability in hapuka could be potentially related to a unique life history of extended pelagic durations up to 4 years. [ABSTRACT FROM AUTHOR]

A conventional gas metal arc welding (GMAW) butt-joining process has been modeled using a two-way fully coupled, transient, thermal-mechanical finite-element procedure. To achieve two-way thermal-mechanical coupling, the work of plastic deformation resulting from potentially high thermal stresses is allowed to be dissipated in the form of heat, and the mechanical material model of the workpiece and the weld is made temperature dependent. Heat losses from the deposited filler-metal are accounted for by considering conduction to the adjoining workpieces as well as natural convection and radiation to the surroundings. The newly constructed GMAW process model is then applied, in conjunction with the basic material physical-metallurgy, to a prototypical high-hardness armor martensitic steel (MIL A46100). The main outcome of this procedure is the prediction of the spatial distribution of various crystalline phases within the weld and the heat-affected zone regions, as a function of the GMAW process parameters. The newly developed GMAW process model is validated by comparing its predictions with available open-literature experimental and computational data. [ABSTRACT FROM AUTHOR]

Juvenile and adult reef fishes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal movements of adult and juvenile reef fishes at Lizard Island, Great Barrier Reef was examined. The first experiment compared the movements of fishes to small patch reefs where reef noise was broadcast, with those to silent reefs. No significant responses were found in the 79 adults that were collected, but the 166 juveniles collected showed an increased diversity each morning on the reefs with broadcast noise, and significantly greater numbers of juveniles from three taxa (Apogonidae, Gobiidae and Pinguipedidae) were collected from reefs with broadcast noise. The second experiment compared the movement of adult and juvenile fishes to reefs broadcasting high (>570 Hz), or low (<570 Hz) frequency reef noise, or to silent reefs. Of the 122 adults collected, the highest diversity was seen at the low frequency reefs; and adults from two families (Gobiidae and Blenniidae) preferred these reefs. A similar trend was observed in the 372 juveniles collected, with higher diversity at the reefs with low frequency noises. This preference was seen in the juvenile apogonids; however, juvenile gobiids were attracted to both high and low sound treatments equally, and juvenile stage Acanthuridae preferred the high frequency noises. This evidence that juvenile and adult reef fishes orientate with respect to the soundscape raises important issues for management, conservation and the protection of sound cues used in natural behaviour. [ABSTRACT FROM AUTHOR]

Introduction: Inguinal hernia repair is well established as a day-case procedure but little is reported about the outcome for elderly patients.Methods: A retrospective study was undertaken to compare a study group of patients aged 70 and above with a controlled group of patients aged less than 65 who had day-case inguinal hernia repair (Lichtenstein repair) between January 1996 and December 2004.Results: A total of 588 patients (282 in the elderly group and 306 in the control group) were studied. Although there were a larger number of higher-risk (ASA III) patients in the elderly group (P < 0.001), unplanned admission, postoperative symptoms, and satisfaction were comparable with those for the younger group.Conclusion: Day-case inguinal hernia repair can be safely offered to patients aged 70 and above. [ABSTRACT FROM AUTHOR]

This study was carried out to assess the efficacy, complication rate and acceptability of endometrial thermal balloon ablation in a District General Hospital in the South West of England. [ABSTRACT FROM AUTHOR]

Neuronal morphogenesis, synaptogenesis and synaptic plasticity are fundamental aspects of nervous system development. Much of our current understanding of how each of these processes contributes to the establishment and maintenance of neural circuitry has come from a molecular description of specific classes of key molecules. With regard to synapse assembly and function, a family of membrane-associated guanylate kinase homologs (MAGUKs) have emerged as central organizers of multicomponent protein signaling complexes. In particular MAGUKs appear to play fundamental roles in the transport, anchoring and signaling of specific subclasses of synaptic receptors and ion channels. In this review, we will focus on the role that subfamilies of MAGUKs play during the formation, maintenance and plasticity of the vertebrate central nervous system glutamatergic synapse. [ABSTRACT FROM AUTHOR]

A detailed methodology is described for determination of treatment effects on muscle cell protein synthesis and muscle cell protein degradation in a cell culture system. C2C22 mouse myoblasts were treated with growth media containing muscle extracts from bovine treated with different pharmaceutical agents. Radiolabeled amino acids were added to the growth media to determine treatment effects on protein synthesis and protein degradation. Percent protein synthesis was calculated by measuring amino acid uptake as a percentage over internal control. Percent protein degradation was measured using a pulse chase technique. These procedures will allow researchers to determine treatment effects on overall protein synthesis and degradation in vitro in a relatively short amount of time without excessive costs. A second benefit is that animals do not have to be fed radiolabeled feedstuffs. These procedures are not intended to elucidate the mechanisms behind pharmaceutical enhancement of muscle cell protein synthesis or protein degradation. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The initial diagnosis of acute pancreatitis is often based on clinical criteria together with elevations of serum amylase and lipase. A reliable bedside urine test could facilitate the early diagnosis of pancreatitis. We evaluated a rapid urine amylase test (Rapignost) by using post-ERCP hyperamylasemia as a human model of acute development of hyperamylasemia suggestive of pancreatitis. METHODS: Seventy-five patients undergoing ERCP prospectively evaluated. Patients with renal insufficiency, hyperlipidemia, or hyperglycemia were excluded. Before ERCP, patients had serum amylase and lipase measured, and urine amylase tested with the Rapignost test strip. At 4 and 16-24 h post-ERCP, a serum and urine (test strip) amylase were measured again; the adequacy of urine collection was verified by measuring a 2-h creatinine clearance. Patients were clinically assessed for the development of clinical pancreatitis. The concordance of the strip result with post-ERCP hyperamylasemia was assessed. RESULTS: The sensitivity of the test strip for the detection of hyperamytasemia was greatest at 16-24 h post-ERCP (78%). Specificity was uniformally high (100% specificity at 16-24 h post-procedure). The test strip was positive in all cases of clinical pancreatitis. Of three cases of clinically evident ERCP-induced pancreatitis, only one was urine test strip positive by 4 h post-procedure. CONCLUSIONS: Using post-ERCP hyperamylasemia as a model, the Rapignost rapid urine amylase test strip was only marginally sensitive but highly specific for hyperamylasemia. The urine test strip was positive in all cases of clinical pancreatitis and may be a useful bedside test for the diagnosis of acute pancreatitis. [ABSTRACT FROM AUTHOR]

Objective: To examine the differences in physician satisfaction associated with open- versus closed-model practice settings and to evaluate changes in physician satisfaction between 1986 and 1997. Open-model practices refer to those in which physicians accept patients from multiple health plans and insurers (i.e., do not have an exclusive arrangement with any single health plan). Closed-model practices refer to those wherein physicians have an exclusive relationship with a single health plan (i.e., staff- or group-model HMO).Design: Two cross-sectional surveys of physicians; one conducted in 1986 (Medical Outcomes Study) and one conducted in 1997 (Study of Primary Care Performance in Massachusetts).Setting: Primary care practices in Massachusetts.Participants: General internists and family practitioners in Massachusetts.Measurements: Seven measures of physician satisfaction, including satisfaction with quality of care, the potential to achieve professional goals, time spent with individual patients, total earnings from practice, degree of personal autonomy, leisure time, and incentives for high quality.Results: Physicians in open- versus closed-model practices differed significantly in several aspects of their professional satisfaction. In 1997, open-model physicians were less satisfied than closed-model physicians with their total earnings, leisure time, and incentives for high quality. Open-model physicians reported significantly more difficulty with authorization procedures and reported more denials for care. Overall, physicians in 1997 were less satisfied in every aspect of their professional life than 1986 physicians. Differences were significant in three areas: time spent with individual patients, autonomy, and leisure time (P < or =.05). Among open-model physicians, satisfaction with autonomy and time with individual patients were significantly lower in 1997 than 1986 (P < or =.01). Among closed-model physicians, satisfaction with total earnings and with potential to achieve professional goals were significantly lower in 1997 than in 1986 (P < or =.01).Conclusions: This study finds that the state of physician satisfaction in Massachusetts is extremely low, with the majority of physicians dissatisfied with the amount of time they have with individual patients, their leisure time, and their incentives for high quality. Satisfaction with most areas of practice declined significantly between 1986 and 1997. Open-model physicians were less satisfied than closed-model physicians in most aspects of practices. [ABSTRACT FROM AUTHOR]

The sensory basis of rheotaxis (orientation to currents) was investigated in the blind Mexican cave fish, Astyanax fasciatus. An unconditioned rheotactic response to uniform velocity flows was exhibited, with a threshold of less than 3 cm s−1. Disabling the entire lateral line or the superficial neuromast receptor class increased the rheotactic threshold to greater than 9 cm s−1. A pharmacological block of the lateral line canal system alone had no effect. These results demonstrate that the superficial lateral line system controls rheotaxis at low current velocities. The effect of pairing an odor stimulant with the water current dropped the rheotactic threshold to less than 0.4 cm s−1. This study provides a clear behavioral role for the superficial neuromasts where none previously existed, and also establishes a link between the mechanosensory lateral line and olfactory systems in the olfactory search behavior of the cave fish. [ABSTRACT FROM AUTHOR]

In an extension of our prior studies with methotrexate and vinca alkaloids, three additional drug combinations incorporating an S-phase-specific antimetabolite and an agent inducing blockade at mitosis or G2 were found to exhibit potent schedule-dependent synergism against the L1210 leukemia. Combinations employed include cytosine arabinoside with vindesine and methotrexate with teniposide (VM-26) or the -deaza-pteridine derivative, NSC 181,928. Synergism was observed following sequential administration (antimetabolite given 24 h before the second agent), but effects following simultaneous administration or sequential administration in the reverse order (antimetabolite given 24 h after the second agent) were only additive. [ABSTRACT FROM AUTHOR]

Extracellular recording techniques were used to record the responses of medial nucleus cells and posterior lateral line nerve fibers in mottled sculpin, Cottus bairdi, and goldfish, Carassius auratus, to a 50-Hz dipole source (vibrating sphere). Responses were characterized in terms of (1) receptive fields that relate responsiveness (spike rate and phase-locking) to the location of the source along the length of the fish, (2) input-output functions that relate responsiveness to vibration amplitude for a fixed source location, and (3) peri-stimulus time histograms that relate responsiveness to time during a sustained period of vibration. Relative to posterior lateral line nerve fibers, medial nucleus cells in both species were similar in showing (1) lower spontaneous and evoked rates of spike activity, (2) greater degrees of adaptation, (3) greater heterogeneity in all response characteristics, and (4) evidence for inhibitory/excitatory interactions. Whereas receptive fields of nerve fibers in both species faithfully reflect both pressure gradient amplitudes (with rate changes) and directions (with phase-angle changes) in the stimulus field, receptive fields of medial nucleus were more difficult to relate to the stimulus field. Some, but not all, receptive fields could be modeled with excitatory center/inhibitory surround and inhibitory center/excitatory surround organizations. [ABSTRACT FROM AUTHOR]

Mutations at the recessive reeler locus ( rl) on mouse Chromosome (Chr) 5 result in abnormal development of multiple central nervous system components, including the cerebral and cerebellar cortices. These abnormalities are characterized by highly disorganized laminar structures thought to have arisen from a post-migration failure of neuronal organization events that are probably mediated through cell-cell interactions. As a result of a mutagenesis scheme designed to generate visible recessive mutations induced by the drug chlorambucil, we had previously recovered a new allele of the reeler locus ( rl) that is likely to involve a deletion based on the known mechanisms of chlorambucil action. We have constructed a high-resolution genetic map from two intercrosses segregating this allele. Our first cross, in which the mutation was outcrossed to the 101 strain prior to intercrossing, consisted of 196 meioses and resulted in the positioning of four loci proximal to rl, with D5Mit1 being the closest (2.6±1.1 cM). The second cross consisted of intercrossing rl heterozygotes derived from an outcross to the C57BL/6 strain. A total of 318 mice (636 meioses) gave rise to a panel of 41 recombinants, which were used to map a total of 14 loci within a 6.4-cM interval bounded by D5Mit1 and the En-2 gene. A yeast artificial chromosome contig consisting of clones containing two of these loci, D5Mit72 (located 0.31 cM distal to rl), and D5Mit61 (no recombinants with rl), has been assembled and is being used to locate the rl gene. [ABSTRACT FROM AUTHOR]

Objective: To determine whether there is variability in the structure and process of ventilatory care in intensive care units (ICUs) of the hospitals of Southwestern Ontario.Design: Self-administered questionnaire-based survey.Setting: ICUs of selected community and teaching hospitals of Southwestern Ontario.Participants: Head of respiratory therapy service of respective hospitals; in those hospitals without respiratory therapists, the ICU nurse manager.Intervention: Self-administered questionnaire.Outcome Measure(s): The availability of different models of ventilators and respiratory therapist and physician coverage were assessed. In addition, the use of clinical practice guidelines, respiratory therapists, and the nursing role in ventilatory care were determined.Results: In general, the structure of ventilatory care, including availability of different modes of ventilation, and coverage by respiratory therapists and physicians was more comprehensive in larger hospitals. However, the availability of some modes of ventilation varied more than expected among hospitals of comparable size. Similarly, variability in the process of ventilatory care, defined by the availability of clinical practice guidelines and the roles of respiratory therapists varied both within and among hospitals of different size.Conclusions: The structure and process of ventilatory care in this sample of Southwestern Ontario ICUs was found to be variable. Not all this variability could be accounted for by hospital size, suggesting a potential for improvement in overall ventilatory care. Further study is required before any specific recommendations can be considered. [ABSTRACT FROM AUTHOR]

Eye movements were produced in an elasmobranch preparation by electrical stimulation of the horizontal canal ampullary nerves. A pseudorandom binary sequence of stimulus pulse trains was delivered bilaterally. Eye position during this stimulus was cross-correlated with the stimulus pattern to obtain a linear model of the response. Sums of exponential functions were fitted to the crosscorrelogram data to estimate time-constants and transfer functions. The data was examined in the frequency domain by using Fourier transformation. The response is accurately described by a second order linear filter, which is essentially a low pass filter with a cutoff at 0.22 Hz. This nearly two octaves below the cutoff frequency of the eye motor plant, which has been estimated by the same method. Our data shows that there is no central phase compensation or prediction which might offset the substantial delay in eye motor plant response. We hypothesise that the necessary phase compensation may be achieved by driving the vestibulo-ocular reflex with sensory neurons having a phase advance at high frequency. [ABSTRACT FROM AUTHOR]

Extracellular single-unit recordings were made from central vestibular units responding to horizontal head rotation in antarctic fish ( Pagothenia borchgrevinki) at temperatures below 0 °C. The frequency of head rotation was varied between 0.05-16 Hz and the results were analysed in terms of the phase and gain of the response with respect to the stimulus. The model of the peripheral vestibular system derived by Hartmann and Klinke (1980) was fitted to the data from antarctic fish in order to obtain a quantitative comparison of vestibular function at two different temperatures. Despite the 20 °C temperature difference, and the different recording sites (primary afferents in the goldfish, and central vestibular units in the antarctic fish) vestibular function in antarctic fish is comparable to that previously reported in goldfish. [ABSTRACT FROM AUTHOR]

Recordings were made from central vestibular neurons responding to horizontal head rotation in antarctic fish, Pagothenia borchgrevinki, at a temperature close to 0 °C. The spontaneous activity of these units varied between 0 and 56 Imp/s with a mean value of 20. Almost all units responded to horizontal rotation with a maximum firing rate that was approximately in phase with head velocity, either towards the recording side (type I units) or away from the recording side (type II), with no alteration of firing pattern during saccadic eye movements. The mean gain of these units was 2.6 Imp/s/ℴ/s at 0.35 Hz which is higher than that reported for central vestibular neurons in other fish. [ABSTRACT FROM AUTHOR]

Considerable evidence has been accumulated to demonstrate that sensitive tumor cells in experimental animals take up and retain at least some effective anticancer drugs to a greater extent than normal tissues, thus providing a greater degree of exposure and accounting for the selective effect of the drugs. In sensitive cells, DNA synthesis is inhibited for prolonged periods, whereas in cells less sensitive the time of inhibition is shorter. In those cases examined where a metabolite, formed intracellularly, is the active form of the agent, the metabolite is produced and is retained to a greater extent than in normal tissues. [ABSTRACT FROM AUTHOR]

Pagothenia borchgrevinki ranging in size from 63 to 245 mm were captured from beneath sea ice in McMurdo Sound by fishing and diver collection. Changes in ocular morphology with increasing body size were measured, and assessed in relation to ingested prey. Relative eye size was highest among smaller fish (<100mm total length), and declined with increasing fish size. This was accompanied by a decrease in cone density in the retina from a maximum of 14,200 mm in the smallest fish examined (63 mm), to 1000 mm in a 220 mm long fish. Theoretical acuity was lowest among fish at either end of the size range examined (minimum separable angle 40-50′) but approximately constant over the remainder of the size range (25-40′). Rod density also decreased with increasing body size but rod numbers per unit visual arc were relatively constant, except in the smallest fish, where angular rod density was low. The same prey taxa occurred in fish of all sizes; however, prey items smaller than about 1.5 mm were not taken by fish of any body size. [ABSTRACT FROM AUTHOR]

The visual threshold for food-location in the antarctic fish Pagothenia borchgrevinki, is compared with light conditions and food availability under the ice. Even under the most favourable conditions for vision, P. borchgrevinki is operating close to its visual threshold and must often depend on non-visual mechanisms of prey detection. [ABSTRACT FROM AUTHOR]

At ambient sub-zero temperatures, muscles from antarctic fish produce spontaneous postsynaptic currents (MEPCs) of significantly shorter duration than those of temperate fishes. Fast decay of antarctic MEPCs is a predictable consequence of the increased membrane fluidity attributable to fatty acid unsaturation in cold-adapted animals. [ABSTRACT FROM AUTHOR]

Over the summer, BDJ readers were surveyed about the BDJ as part of a series of BDJ surveys conducted since 1992. As well as assessing general views about the BDJ, the survey also aimed to discover how successful the 1998 BDJ redesign had been in incorporating reader's views from earlier surveys. The findings from the 1999 survey showed that the BDJ and BDA News continue to be the most read dental publications. Readers turn to the BDJ before any other UK dental journal for finding a job and reports on research. The full results of the survey are reported below. [ABSTRACT FROM AUTHOR]

Extraocular muscles of a teleost fish, Girella tricuspidata, contain a predominantly phasic stretch receptor, which consists of fine beaded nerve terminals within the red portion of the muscle. [ABSTRACT FROM AUTHOR]