Unemployment and the smoothness of consumption in business cycle models

The permanent income hypothesis means that dynamic general equilibrium models fail to produce a hump-shaped response for consumption even if they do so for other variables. This article shows that the introduction of non-separable preferences and unemployment can solve this problem

What tone teaches us about language

In ‘Tone: Is it different?’ (Hyman 2011a), I suggested that ‘tone is like segmental phonology in every way—only more so’, emphasizing that there are some things that only tone can do. In this presidential address my focus extends beyond phonology, specifically addressing what tone tells us about the integration (vs. compartmentalization) of grammar. I discuss some rather striking examples that demonstrate problems for the strict separation of phonology, morphology, and syntax, each time posing the question, ‘What else is like this outside of tone?’. A particularly interesting property that is strictly limited to tone is what I term syntagmatic relativity. I suggest that the uniqueness of tonal phenomena is due to the versatility of pitch, which can be manipulated with a wide range of linguistic functions. Given this versatility, I end by considering the question, ‘Why isn’t tone universal?’.*

Effects of exercise-induced arterial hypoxemia on limb muscle fatigue and performance

1. Reductions in arterial O2 saturation (−5% to −10% SaO2 below rest) occur over time during sustained heavy-intensity exercise in a normoxic environment, caused primarily by the effects of acid pH and increased temperature on the position of the HbO2 dissociation curve. 2. We prevented the desaturation incurred during exercise at ∼90% √O2 MAX via increased fraction of inspired O2 (FiO2) (0.23 to 0.29) and showed that exercise time to exhaustion was increased. 3. We used supramaximal magnetic stimulation (1–100 Hz) of the femoral nerve to test for quadriceps fatigue. We used mildly hyperoxic inspirates (FiO2 0.23 to 0.29) to prevent O2 desaturation. We then compared the amount of quadriceps fatigue incurred following cycling exercise at SaO2 91% vs 98% with each trial carried out at identical work rates and for equal durations. 4. Preventing the normal exercise-induced O2 desaturation prevented about one-half the amount of exercise-induced quadriceps fatigue; plasma lactate and effort perception were also reduced. In a subset of less fit subjects who showed only minimal arterial hypoxaemia during sustained exercise (SaO2 ∼95%), breathing a mildly hypoxic inspirate (FiO2 0.17; SaO2 ∼88%) exacerbated the quadriceps fatigue. 5. We conclude that the normal exercise-induced O2 desaturation during heavy-intensity endurance exercise contributes significantly to exercise performance limitation in part because of its effect on locomotor muscle fatigue

Progressive auditory neuropathy in patients with Leber's hereditary optic neuropathy

Objective: To investigate auditory neural involvement in patients with Leber's hereditary optic neuropathy (LHON).Methods: Auditory assessment was undertaken in two patients with LHON. One was a 45 year old woman with Harding disease (multiple-sclerosis-like illness and positive 11778mtDNA mutation) and mild auditory symptoms, whose auditory function was monitored over five years. The other was a 59 year old man with positive 11778mtDNA mutation, who presented with a long standing progressive bilateral hearing loss, moderate on one side and severe to profound on the other. Standard pure tone audiometry, tympanometry, stapedial reflex threshold measurements, stapedial reflex decay, otoacoustic emissions with olivo-cochlear suppression, auditory brain stem responses, and vestibular function tests were undertaken.Results: Both patients had good cochlear function, as judged by otoacoustic emissions ( intact outer hair cells) and normal stapedial reflexes ( intact inner hair cells). A brain stem lesion was excluded by negative findings on imaging, recordable stapedial reflex thresholds, and, in one of the patients, olivocochlear suppression of otoacoustic emissions. The deterioration of auditory function implied a progressive course in both cases. Vestibular function was unaffected.Conclusions: The findings are consistent with auditory neuropathy - a lesion of the cochlear nerve presenting with abnormal auditory brain stem responses and with normal inner hair cells and the cochlear nucleus (lower brain stem). The association of auditory neuropathy, or any other auditory dysfunction, with LHON has not been recognised previously. Further studies are necessary to establish whether this is a consistent finding

Effect of expiratory muscle fatigue on exercise tolerance and locomotor muscle fatigue in healthy humans

High-intensity exercise (> or =90% of maximal O(2) uptake) sustained to the limit of tolerance elicits expiratory muscle fatigue (EMF). We asked whether prior EMF affects subsequent exercise tolerance. Eight male subjects (means +/- SD; maximal O(2) uptake = 53.5 +/- 5.2 ml.kg(-1).min(-1)) cycled at 90% of peak power output to the limit of tolerance with (EMF-EX) and without (CON-EX) prior induction of EMF and for a time equal to that achieved in EMF-EX but without prior induction of EMF (ISO-EX). To induce EMF, subjects breathed against an expiratory flow resistor until task failure (15 breaths/min, 0.7 expiratory duty cycle, 40% of maximal expiratory gastric pressure). Fatigue of abdominal and quadriceps muscles was assessed by measuring the reduction relative to prior baseline values in magnetically evoked gastric twitch pressure (Pga(tw)) and quadriceps twitch force (Q(tw)), respectively. The reduction in Pga(tw) was not different after resistive breathing vs. after CON-EX (-27 +/- 5 vs. -26 +/- 6%; P = 0.127). Exercise time was reduced by 33 +/- 10% in EMF-EX vs. CON-EX (6.85 +/- 2.88 vs. 9.90 +/- 2.94 min; P < 0.001). Exercise-induced abdominal and quadriceps muscle fatigue was greater after EMF-EX than after ISO-EX (-28 +/- 9 vs. -12 +/- 5% for Pga(tw), P = 0.001; -28 +/- 7 vs. -14 +/- 6% for Q(tw), P = 0.015). Perceptual ratings of dyspnea and leg discomfort (Borg CR10) were higher at 1 and 3 min and at end exercise during EMF-EX vs. during ISO-EX (P < 0.05). Percent changes in limb fatigue and leg discomfort (EMF-EX vs. ISO-EX) correlated significantly with the change in exercise time. We propose that EMF impaired subsequent exercise tolerance primarily through an increased severity of limb locomotor muscle fatigue and a heightened perception of leg discomfort

Exercise-induced respiratory muscle fatigue: implications for performance

It is commonly held that the respiratory system has ample capacity relative to the demand for maximal O-2 and CO2 transport in healthy humans exercising near sea level. However, this situation may not apply during heavy-intensity, sustained exercise where exercise may encroach on the capacity of the respiratory system. Nerve stimulation techniques have provided objective evidence that the diaphragm and abdominal muscles are susceptible to fatigue with heavy, sustained exercise. The fatigue appears to be due to elevated levels of respiratory muscle work combined with an increased competition for blood flow with limb locomotor muscles. When respiratory muscles are prefatigued using voluntary respiratory maneuvers, time to exhaustion during subsequent exercise is decreased. Partially unloading the respiratory muscles during heavy exercise using low-density gas mixtures or mechanical ventilation can prevent exercise-induced diaphragm fatigue and increase exercise time to exhaustion. Collectively, these findings suggest that respiratory muscle fatigue may be involved in limiting exercise tolerance or that other factors, including alterations in the sensation of dyspnea or mechanical load, may be important. The major consequence of respiratory muscle fatigue is an increased sympathetic vasoconstrictor outflow to working skeletal muscle through a respiratory muscle metaboreflex, thereby reducing limb blood flow and increasing the severity of exercise-induced locomotor muscle fatigue. An increase in limb locomotor muscle fatigue may play a pivotal role in determining exercise tolerance through a direct effect on muscle force output and a feedback effect on effort perception, causing reduced motor output to the working limb muscles

Comparison of the Knowledge in Core Policies of Essential Drug List Among Medical Practitioners and Medical Students in Galle, Sri Lanka

Selection of the best and safest medicine should be one of the national economic policies in a country for good health care services. Introduction of detailed module in rational use of medicine (RUM) to pharmacology syllabus needed prior analysis of the existing knowledge among health care workers. Therefore we assessed the knowledge and attitudes of essential drug list (EDL) on medical practitioners (MPs) and medical students (MSs). Forty two MPs and 120 MSs from hospital and Faculty of Medicine were given a pretested structured questionnaire related to core policies of EDL, contents, criteria for selection and time frame for revision in RUM. Our study showed that only 29% of MPs were confident about their knowledge in EDL and 17% of them had marked it as don’t know. Study was expanded for quantitative analysis of the knowledge on the core policies of EDL on them. Knowledge on contents, criteria for selection and the time frame for revision of EDL were 63%, 83% and 17% in MPs. Of MSs, 87% had sound knowledge in core contents, 32% in criteria for selection and only 50% of MSs were aware about the correct time frame of revision of EDL. Knowledge in contents of EDL was higher in MSs (87%) than MPs(63&). MPs were not aware about EDL preparing criteria such as inclusion of generic names, common ailment, majority ailments of the people (59%, 56% and 56% respectively). In contrast, MSs had > 93% of the knowledge in all three areas. However MSs had poorer knowledge (32%) in criteria for selection of EDL than MPs (83%). Knowledge in time frame for revision of EDL was 17% in MPs and 50% in MSs. We found that MPs in the service were not convinced about their knowledge in EDL. Deficiency was significant in the core contents of the EDL preparation. Therefore we suggest that MPs need repetitive in-service training programme for practicing of RUM in the national health facilities. We need to reiterative programme in the core curriculum regarding the criteria for EDL selection. Though MSs had good knowledge in content of EDL, they are poor in criteria for selection and time frame for revision

Possible role for cell-surface carbohydrate-binding molecules in lymphocyte recirculation.

We are investigating the hypothesis that carbohydrate-binding molecules on the cell surface are involved in the recirculation of lymphocytes from the bloodstream into lymphoid organs. This phenomenon requires the specific attachment of circulating lymphocytes to the endothelial cells of postcapillary venules. Using an in vitro assay to measure the adhesive interaction between lymphocytes and postcapillary venules, we have found that L-fucose, D mannose, and the L-fucose-rich, sulfated polysaccharide fucoidin specifically inhibit this binding interaction. L-fucose shows stereo-selective inhibitory activity at concentrations greater than 18 mM while fucoidin produces 50% inhibition at approximately 1-5 X 10(-8) M. Fucoidin appears to interact with the lymphocyte, and not the postcapillary venule, to inhibit binding. These data suggest that cell surface carbohydrates (fucoselike) and carbohydrate-binding molecules (cell surface lectins) may contribute to the specific attachment of lymphocytes to postcapillary venules