Given Level Of Activity Research Articles

Objective measures of moderate to vigorous physical activity are associated with higher distal limb bone strength among elderly men.

Our aim was to determine the association between objectively measured physical activity (PA) and bone strength of the distal limbs among older men. We studied 994 men from the MrOS cohort study (mean age 83.9) who had repeat (Year 7 and 14) 5-day activity assessment with at least 90% wear time (SenseWearPro3 Armband) and Year 14 measures using high resolution peripheral quantitative tomography (HR-pQCT) (Scanco). Total energy expenditure (TEE), total steps per day, peak cadence (mean of top 30steps/min over 24h) and time spent in a given level of activity: sedentary (reference, <1.5 metabolic equivalents of task [METs]), light (1.5 to <3 METs), or moderate to vigorous physical activity(MVPA: ≥3 METs) were calculated as mean over the two time points. Estimated failure load was determined from HR-pQCT data using finite element analysis. We used standardized variables and adjusted for potential confounders using linear regression. The means ±SDs for daily activity were: 2338±356kcal/d [TEE]; 5739±2696steps/day [step count], 60±20cpm [peak cadence], 67±28min/d [light activity], and 85±52min/d [MVPA]. Higher TEE, step count, and peak cadence were each associated with higher failure load of the distal radius (effect sizes respectively: 0.13 [95% CI: 0.05, 0.20], 0.11 [95% CI: 0.04, 0.18], and 0.08 [95% CI: 0.01, 0.15]) and higher failure load of the distal tibia (effect sizes respectively 0.21 [95% CI: 0.13, 0.28], 0.19 [95% CI: 0.13, 0.26], 0.19 [95% CI, 0.13, 0.25]). Time spent in MVPA vs. time sedentary was related to bone strength at both sites after adjustment, whereas time spent in light activity vs. time sedentary was not. TEE was associated with compartmental area and BMD parameters at distal tibia, but only area parameters at the distal radius. In summary, MVPA over a 7-year period of time may have a modest association with bone strength and geometry among older men.

Feet, heat and scallops: what is the cost of anthropogenic disturbance in bivalve aquaculture?

The effects of unnatural disturbances on the behaviour and energetics of animals are an important issue for conservation and commercial animal production. Biologging enables estimation of the energy costs of these disturbances, but not specifically the effect these costs have on growth; a key outcome measure for animal farming enterprises. We looked at how natural and anthropogenically induced activity and energy expenditure of king scallops Pecten maximus varies with temperature. These data were then used to model growth time of king scallops reared in an aquaculture facility under different temperatures and anthropogenic disturbance levels. The scallops exhibited a typical total metabolic rate (MR)–temperature curve, with a peak reached at a middling temperature. The percentage of their total MR associated with spinning and swimming, behavioural responses to disturbance, was considerable. Interestingly, as temperature increased, the activity MR associated with a given level of activity decreased; a hitherto unreported relationship in any species. The model results suggest there is a trade-off in the ambient temperature that should be set by hatcheries between the optimal for scallop growth if completely undisturbed versus mitigating against the energy costs elicited by anthropogenic disturbance. Furthermore, the model indicates that this trade-off is affected by scallop size. Aquaculture facilities typically have controls to limit the impact of human activities, yet the present data indicate that hatcheries may be advised to consider whether more controls could further decrease extraneous scallop behaviours, resulting in enhanced scallop yields and improved financial margins.

Comparing Efficiency of Public Universities among European Countries: Different Incentives Lead to Different Performances

AbstractThis paper analyses the relationship between the public funding systems of higher education in Italy and the Netherlands and their universities' performances. Empirically, an efficiency analysis on 13 Dutch and 58 Italian public universities is conducted. The findings show that the relative efficiency of Italian and Dutch universities is strongly influenced by the policy perspective adopted. If the goal is to realise the European goals and minimise resources employed for obtaining a high number of graduates, Dutch universities turn out to be more efficient. However, Italian universities are much more efficient if the priority is to minimise the costs for a given level of activity, such as number of students.

Comparing Efficiency of Public Universities Among European Countries: Different Incentives Lead to Different Performances

In this paper we study the feasibility of the European EU2020 goal of increasing the number of higher education graduates, considering large differences in incentives and funding schemes between countries in Europe. We conduct an efficiency analysis on 13 Dutch and 58 Italian public universities. Our findings show that the relative efficiency of Italian and Dutch universities is strongly influenced by the policy perspective adopted. If the goal is to realize the European goals and minimize resources employed for obtaining a high number of graduates, Dutch universities turn out to be more efficient. However, Italian universities are much more efficient if the priority is to minimize the costs for a given level of activity, such as number of students. The main policy consequence of our findings is that it will be hard to realize European goals if not all countries have incentive scheme that are in line with these goals.

Hierarchic system of QSAR models (1D–4D) on the base of simplex representation of molecular structure

In this work, a hierarchic system of QSAR models from 1D to 4D is considered on the basis of the simplex representation of molecular structure (SiRMS). The essence of this system is that the QSAR problem is solved sequentially in a series of the improved models of the description of molecular structure. Thus, at each subsequent stage of a hierarchic system, the QSAR problem is not solved ab ovo, but rather the information obtained from the previous step is used. Actually, we deal with a system of solutions defined more exactly. In the SiRMS approach, a molecule is represented as a system of different simplex descriptors (tetratomic fragments with fixed composition, structure, chirality and symmetry). The level of simplex-descriptor detail increases consecutively from 1D to 4D representations of molecular structure. It enables us to determine the fragments of structure that promote or interfere with the given biological activity easily. Molecular design of compounds with a given level of activity is possible on the basis of SiRMS. The efficiency of the method is demonstrated for the example of the analysis of substituted piperazines affinity for the 5-HT1A receptor.

Clinical Presentations of Myocarditis

Although, myocarditis usually is caused by a viral or postviral autoimmune response, it may result from virtually any infectious agent (rickettsia, bacteria, spirochetes, fungus, and protozoa), drugs and chemicals, physical agents, or as part of an underlying inflammatory or autoimmune process. All the infectious etiologies are characterized by inflammation of the myocardium in response to a systemic dissemination of the offending infectious agent. Patients with viral or postviral autoimmune myocarditis rarely display signs or symptoms of active viral infection, making recognition of this entity more difficult. Most viruses enter through the upper respiratory or gastrointestinal system. Once the virus is released from the local immune barriers it disseminates to the remainder of the body. From 3.5% to 5% of individuals who have infections from cardiotropic viruses will replicate virus in their heart with associated death of myocytes (myocytolysis). Initially, a nonspecific macrophage and IgM antibody reaction results in myocardial inflammation and further myocyte loss. By 14 days an IgG-specific antibody response promotes death of the virus and healing of the inflammatory cardiac reaction. Animal models have demonstrated that viral myocarditis is not associated with a uniform presentation but is influenced by the offending viral agent, the immune response to the virus, and the ability to eliminate viral pathogen from the heart. Patients who have viral myocarditis have similar variations in their symptoms, physical findings, and ‘‘natural history.’’ After the viral illness, there is a variable delay followed by cardiac symptoms in those who have myocarditis, including congestive heart failure, arrhythmia, embolic events, or acute ischemia. Unfortunately, the symptoms of myocarditis are usually nonspecific and include fatigue and weakness as a result of low cardiac output, dyspnea or othopnea caused by elevated filling pressures, chest pain from pericarditis or acute ischemia, and palpitations from arrhythmia. Physical findings are also nondescript but often include a heart rate greater than expected for a given level of activity, the development of gallop rhythms, rubs caused by pericardial irritation, murmurs related to ventricular remodeling, and decreased intensity in the first heart sound. This article concentrates on the clinical presentations of myocarditis, including arrhythmias, acute myocardial infarction, cardiovascular collapse, rapidly progressive cardiomyopathy or arrhythmias, and restrictive cardiomyopathy. Clues to the identification of myocarditis in other systemic illnesses and subacute cardiomyopathy development (perhaps leading to dilated cardiomyopathy) also are discussed.

Categorisation of Children??s Physical Activity Levels Using Accelerometry

0211 Previous work using accelerometers has produced cut-points to categorise different intensities of activity in adults and children (Freedson, 1998; Puyau, 2002; Reilly, 2003). Further research is required to investigate if the accelerometer output for a given activity level is Influenced by the age of the child and thus necessitate the development of age-specific cut-points for categorisation purposes. PURPOSE: To determine the Influence of a child's age on accelerometry output for a given level of activity as defined by the Children's Physical Activity Form (CPAF, O'Hara, 1989), as sedentary, light, moderate and vigorous activities. METHODS: 37, 3–4yrs old, 43, 5–8 yrs old and 32, 9–10 yrs old children took part in age-specific physical activity classes, incorporating sedentary, light, moderate and vigorous activities. Activity was monitored simultaneously by direct observation using CPAF and also CSA accelerometers. Accelerometer output was calculated as counts per minute (cpm) and a corresponding CPAF score (60 = sedentary; 120 = light; 180 = moderate; 240 = vigorous) was produced for every minute of the class. Only those minutes consisting exclusively of a single activity category were analysed. One-way ANOVA and Tukey's pairwise comparisons were performed on each activity level across the three age-groups. RESULTS: The table shows that in sedentary and moderate activity, there is no significant difference in accelerometer cpm between age-groups. There is a significant difference† in cpm between the 5–8 age-group and the other two groups in light activity. In the vigorous activity intensity category, a significant difference‡ in cpm was found between 9–10yrs and the other age-groups. CONCLUSIONS: These data suggest that children's age may Influence physical activity categorisation when physical activity is measured using accelerometry.Table

Waist Circumference, Visceral Obesity, and Cardiovascular Risk

Waist Circumference, Visceral Obesity, and Cardiovascular Risk

A randomised controlled trial of the costs of hospital as compared with hospital in the home for acute medical patients

To test the cost effectiveness of Hospital in the Home compared to hospital admission for acute medical conditions. Randomised controlled trial at the Prince of Wales Hospital, Sydney, from October 1995 to February, 1997; 100 patients with acute medical conditions admitted through the Emergency Department. The Hospital in the Home (HITH) group costs per separation ($1,764, CI 95% $1,416-$2,111, n = 50) were significantly lower (p < 0.0001, Mann-Whitney U-Wilcoxon Rank Sum) than the control group hospital separation ($3,614, CI 95% $2,881.37-$4,347.27, n = 47) with no significant difference in clinical outcomes, and comparable or better user satisfaction. Given the favourable clinical outcomes the HITH model produces at a lower cost, the cost-effectiveness of the care mode is high, and the allocative efficiency favourable. As a care model and critical pathway, HITH offers hospitals real bed day savings that can either be used to rationalise resource usage for a given level of activity, or increase throughput.

Coevolution of traits determining migratory tendency: correlated response of a critical enzyme, juvenile hormone esterase, to selection on wing morphology

AbstractMigratory tendency in insects is a complex trait, composed of a suite of correlated behavioural, physiological, morphological and life history traits. We investigate the genetic and physiological basis of the coevolution of this suite of traits using laboratory lines of the wing dimorphic cricket, Gryllus firmus, selected for increasing and decreasing incidence of macroptery. Selection on wing morphology has produced strong direct responses in proportion macropterous as well as correlated (indirect) responses in wing muscle histolysis, flight propensity and fecundity. We investigate the hypothesis that these responses have been mediated by changes in the metabolism of juvenile hormone (JH) during the final nymphal stadium (the critical period for wing morph determination). Previous studies of Gryllus sp. have established that JH titre in this period is determined primarily by the activity of the degradative enzyme, juvenile hormone esterase (JHE). Assays of JHE activity in the final nymphal stadium of the replicated control and selected lines demonstrate highly significant differences in both mean activity and the probability of macroptery for a given level of activity (i.e., the threshold activity required to induce wing formation). These correlated responses in JH metabolism support the general hypothesis that the correlations among traits determining migratory tendency result at least in part from the common influence of JH during the final nymphal stadium. We discuss these results in the context of the quantitative genetic model for the evolution of polygenic, dichotomous traits (the threshold model), and present four general predictions concerning the coevolution of traits associated with ecological (i.e., trophic, life history, behavioural) dimorphisms.

A Model for the Quaternary Structure of the Proteasome Activator PA28

PA28 is a protein activator of the 20S proteasome. It has a native molecular weight of approximately 200,000 and is composed of six 28,000-dalton subunits arranged in a ring-shaped complex. Purified preparations of PA28 contain two polypeptides, alpha and beta, which are about 50% identical in primary structure. It has been unclear whether native PA28 consists of two distinct homohexameric proteins or of a single protein containing both alpha and beta subunits. To distinguish between these possibilities, we prepared antibodies that reacted specifically with either the alpha or beta subunit and used these subunit-specific antibodies in two types of experiments designed to elucidate PA28 quaternary structure. In the first experiment, the alpha and beta subunits were completely co-immunoprecipitated by each subunit-specific antibody, indicating that both subunits were part of a single protein complex. In the second experiment, PA28 was chemically cross-linked using bis(sulfosuccinimidyl)suberate. When the cross-linked products were immunoblotted after SDS-polyacrylamide gel electrophoresis, indistinguishable patterns were obtained with each subunit-specific antibody. These results confirm that the alpha and beta subunits were part of the same protein complex. The pattern of cross-linked products also provided insight as to the relative abundance and arrangement of the subunits within the PA28 complex and indicated that the ring-shaped PA28 hexamer may be composed of alternating alpha and beta subunits with a stoichiometry of (alphabeta)3. PA28 was inactivated by treatment with carboxypeptidase Y, which cleaved Tyr and Ile residues from the carboxyl terminus of the alpha subunit but had very little effect on the beta subunit. This selective and limited proteolysis prevented binding of both alpha and beta subunits to the proteasome and therefore provides additional evidence of the heterodimeric nature of PA28. These results indicate that a short carboxyl-terminal sequence of the alpha subunit is critical for binding of native PA28 to the proteasome. To learn about the relative functions of the alpha and beta subunits, PA28alpha was expressed in Escherichia coli and purified to homogeneity. Purified PA28alpha stimulated proteasome activity but required 5-10-fold greater concentrations than the heterodimeric PA28 to achieve a given level of activity. These results suggest that the heterodimeric structure of PA28 is required for maximal proteasome activation.

Exertional breathlessness in patients with chronic airflow limitation. The role of lung hyperinflation.

There is considerable intersubject variability in the perceived intensity of breathlessness for a given level of activity among patients with chronic airflow limitation (CAL). To examine possible factors contributing to this variability we compared breathing pattern parameters, dynamic operational lung volumes, and Borg dyspnea ratings in 23 patients with severe CAL and in 10 healthy age-matched normal subjects during cycle ergometry to symptom-limitation. Patients with CAL had significantly (p < 0.01) higher levels of ventilation (% maximal voluntary ventilation) for a given work rate (slope of VE(%MVV)/WR(% pred max) = 1.51 +/- 0.18 versus 0.63 +/- 0.10; mean +/- SEM) and greater dynamic lung hyperinflation (DH) (change [delta] in end-expiratory lung volume [EELVdyn] = +0.31 +/- 0.11 L versus -0.16 +/- 0.22 L). Compared with normal subjects at a standardized VE (30 L/min), the CAL group was more breathless Borg = 4 +/- 1 versus 2 +/- 1, p < 0.01) and hyperinflated (EELVdyn = 75 +/- 3 versus 46 +/- 6% TLC, p < 0.001; end-inspiratory lung volume [EILVdyn] = 85 +/- 3 versus 67 +/- 5% TLC, p < 0.01). Within the CAL group, change in Borg ratings correlated with delta VE(%MVV) (r = 0.77, p < 0.001) and with slope of VE(%MVV)/WR(% pred max) (r = 0.48, p < 0.01). Regression analysis selected delta EILVdyn (or delta inspiratory reserve volume [delta IRVdyn]) from various dynamic ventilatory parameters as the strongest predictor of delta Borg (r = 0.63, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Ventilatory and Metabolic Changes as a Result of Exercise Training in COPD Patients

Patients with COPD feel better and are able to sustain a given level of activity longer after a program of exercise training, but the underlying physiologic mechanisms have not been completely elucidated. Since the physical performance of patients with COPD is limited mainly by pathophysiologic derangements of the ventilatory system, the exercise performance can be ameliorated by increasing the level of ventilation that they can sustain or by reducing the ventilatory requirement for a given level of activity. Almost all studies have yielded negative results in patients with COPD in terms of exercise training having the ability to improve VEmax. The only way to reduce the ventilatory requirement is to reduce CO2 output. Lower levels of lactate result in less nonmetabolic CO2 produced by bicarbonate buffering and this is the likely mechanism responsible for a lower ventilatory requirement for work rates above the pretraining anaerobic threshold. We specifically wished to determine whether a program of intensity, frequency, and duration known capable of producing a physiologic training effect in healthy subjects would do so in patients with COPD. Further, we sought to determine whether exercise training at a work rate associated with lactic acidosis is more effective in inducing a training effect in patients with COPD than a work rate not associated with lactic acidosis. Nineteen patients with COPD were selected and performed an incremental test as well as 2 square wave tests at a low and a high work rate. Identical tests were performed after an 8-week program of cycle ergometer training either for 45 min/day at a high work rate or for a proportionally longer time at a low work rate. For the high work rate training group, identical work rates engendered less lactate (4.5 vs 7.2 mEq/L) and less VE (48 vs 55 L/min) after training; the low work rate training group had significantly less lactate and VE decrease (p less than 0.01). Further, in the first group, there was an increase in exercise tolerance averaging 71% in the high constant work rate test. There was a good correlation (r = 0.73, p less than 0.005) between the decrease in blood lactate and the decrease in ventilation. The major findings of this study are that patients with COPD who experience lactic acidosis during exercise can achieve physiologic training responses from a program of endurance training and that training work rates engendering high levels of blood lactate are more effective than work rates eliciting low lactate levels.

The combined effect of solar and geomagnetic activity on high latitude thermospheric neutral winds. Part I. Observations

Long-term averages of Fabry-Perot Interferometer (FPI) observations of the night-time OI ( 1 D) emission at 630 nm from the F-region thermosphere at a high latitude site are presented here. The data base contains measurements of thermospheric neutral winds for every winter period from November 1981 to April 1989 inclusive. This covers nearly one complete solar cycle in terms of the radio and UV/EUV flux variation, from the last solar maximum to the present solar maximum. The instrument is located in Kiruna, Sweden, which is situated at the equatorward edge of the auroral oval at quiet to moderate levels of geomagnetic activity and beneath the oval at higher levels of activity. From this location, the FPI has sampled the response of the upper thermosphere winds at night to a wide range of geomagnetic and solar activity conditions. The data presented here show a significant correlation between the solar radio or EUV fluxes and the response of thermospheric neutral winds to geomagnetic conditions in the auroral oval. For K p < 2 the auroral oval is polewards of Kiruna and neutral winds are similar at solar minimum and solar maximum. At higher levels of geomagnetic activity, for a given level of activity, the neutral winds are a factor of two greater at high levels of solar flux, than at low levels of solar flux. Alternately, the same winds are seen at K p = 3 at high solar flux levels, as at K p = 5 for low flux levels. Comparing the situation for high and low solar activity, for a given level of geomagnetic activity, in the dusk auroral oval, the sunward or westward winds are a factor of two larger at solar maximum. In the midnight period, the equatorward wind is a factor of two larger at high solar activity, compared with low solar activity. In this paper, the observations will be discussed, with the implication that K p is a rather poor indicator of momentum and energy coupling from the solar wind to the upper thermosphere. In a second paper, the solar-terrestrial processes which cause this phenomenon will be discussed and modelled.

Athletic Participation After Myocardial Revascularization: Possibilities and Benefits

Exercise after open heart operation is not only possible but highly desirable. Training increases the efficiency of exercise and therefore decreases myocardial work for any given level of activity. Even before sternal and incisional healing is complete the patient may become physically active. Almost every patient can improve his or her level of fitness safely by following simple guidelines. Exercise treadmill testing is the basis for assessing exercise capacity in cardiac patients. Upper-body exercise is not adequately emphasized in most exercise programs.

Power density of equatorial electric field at L=2.3

Records of the Doppler shift on signals from a VLF transmitter received in the whistler mode are converted to fluctuation electric fields in the equatorial plane at L=2.3 and presented as power spectral densities. The 200 hours of data examined show 2 orders of magnitude variation in the power level as magnetic activity rises, though there is a considerable range of values at a given level of activity. Median values are an order of magnitude below the levels found by balloon extrapolations at what were generally higher latitudes. Simultaneous whistler mode records of azimuthal electric field at longitudes spaced by about 7 hours show such correlations that the electric fields near 1‐hour period must be composed mainly of low order spatial modes. With this assumption a diffusion coefficient at L=2.3 for radially diffusing particles is calculated which shows that at energies up to ∼0.5 MeV, electrostatic diffusion must be very important.

THE LOGIC OF TAX LIMITS: ALTERNATIVE CONSTITUTIONAL CONSTRAINTS ON THE POWER TO TAX

entities, total budgets and total product or income. But setting these problems of electoral psychology aside, are there any purely technical problems that ratio limits seem likely to pose? There are two that seem to us particularly important one relating to whether the limits are effective, and the other relating to whether those effective limits are achieved in the most desirable way. In the simple Leviathan model outlined above, government seeks to maximize its own surplus or income, measured by revenues, R, minus the necessary outlay on public goods and services, G. If it is constrained as R, either in absolute or share-of-income terms, it may seek to provide the necessary G indirectly rather than directly, and thereby increase its surplus, Y. One means of accomplishing this result would be to manipulate the structure of taxes while remaining within the overall uneven constraint. Consider, for example, some publicly provided good such as education. Clearly, the government can achieve a required level, either by direct provision of education (i.e. it can individuals and provide the service free of direct charge) or by subsidizing private provision. And the subsidy in question may take the form of vouchers (or direct subsidy of some other type) or concessions. In principle, each of these alternatives could produce precisely the same outcome, but they clearly involve quite different amounts of nominal revenue. The subsidizing of private activity will typically achieve a larger response per dollar of revenue raised than direct provision; obversely, for any given level of activity, subsidy will typically involve less revenue than direct provision. Subsidies given as direct payments will likewise involve more nominal revenue and a higher nominal government budget than concessions which induce an identical private response. At the very least therefore we should require that such tax expenditures be incorporated into the relevant measure of total revenue for 'share limiť purposes. But this in turn raises the question as to whether we ought also distinguish between subsidies and direct provision; for, as we have observed, an identical amount of revenue can involve a different level of government influence depending on the form of government action. Even if the implicit subsidy embodied in taxexpenditures is made explicit, therefore, the problem associated with translating any given revenue figure into some measure of government output remains. And there are important conceptual issues at stake in this. Is it clear, for example, that we do wish to minimize government output or influence, independently of its revenue cost? Is there a distinction to be drawn between policies which involve revenues passing through the hands of government agencies, and those which do not? We do not attempt to answer these questions here. But it does seem clear that any share limit which accurately reflected what it is we wish to measure would be extremely complex and itself somewhat open to debate, and the problems of electoral ignorance would be correspondingly aggravated. Equally, the extent to which an aggregate revenue limit would succeed in achieving the objective of placing limits on government activity seems open to some doubt. Suppose, however, that in the presence This content downloaded from 157.55.39.171 on Sat, 25 Jun 2016 05:31:38 UTC All use subject to http://about.jstor.org/terms 16 SUPPLEMENT NATIONAL TAX JOURNAL of this maximum share (appropriately defined), government is genuinely constrained. Nevertheless, government can achieve its maximum share in a variety of ways between which the citizentaxpayer behind the veil of ignorance could not be expected to be indifferent. For example, different arrangements will induce different excess burdens: in the extreme case government could exploit instruments considerably beyond their maximum revenue limits and the excess burden induced by the could be many times greater than the revenue raised. There is nothing inherent in the nature of share limits which would give government the incentive to seek out broadly based, minimally distorting taxes. As we have already seen, the government, on the contrary, has the incentive to acquire its revenue limit by the application of very high rates to a base made narrow by strategic concessions.7 Whether these high rates raise much or indeed any revenue is largely beyond the point: the associated excess burdens seem likely to be very substantial indeed.

Decomposition Measures for Financial Analysis

A major characteristic of all living organisms is homeostasis-an equilibrium maintained by a selfregulatory mechanism. When such an equilibriume.g., a human body temperature of 98.6 degrees-is disturbed, forces are set in motion to restore it. It has been suggested by organization theorists [4] and economists [2], that the behavior of business organizations can also be characterized by homeostasis in which optimal (equilibrium) relationships among the various inputs and outputs are determined and efforts are made to maintain them against disturbances. Thus, for any given level of activity, for example, there exist optimal relationships between labor and capital inputs, inventory and sales, cash and shortterm securities, debt and equity capital. The analogy between living organisms and that of business organizations is, however, incomplete since the latter's equilibrium input and output relationships can change over time. Such changes generally result from (a) planned changes by management, such as the increase in the ratio of short-term securities to

The remote sensing approach to censusing

Population censusing continues to be a methodological problem in ecology, particularly for inconspicuous, mobile animals which are spaced over a large area. Whereas most censusing has depended upon capturing such animals, an approach based upon sampling without capture may serve better in many situations. The advantages of non-capture censusing, as reviewed in detail by MARTEN (in press a), are that: (1) The population is sampled with a minimum of disturbance. (2) Multiple sampling of each individual in the population generates samples large enough for precise estimates, even with difficult-to-trap species or low population densities. (3) Sampling bias, so common with trapping, may be avoided. (4) Population density is measured directly, making unnecessary a computed boundary strip to determine the area censused. (5) Measurement of density has high resolution in time and space. MARTEN (in press a) has already applied the non-capture approach in censusing deer mice (Peromyscus), sampling by means of tracks on smoked cards. The basic principle of mark-recapture was employed, where the proportion of known, marked mice in the total population was reflected simply in the proportion of all tracks which were marked. Presented below is a feasibility study of non-capture sampling by means of electronic remote sensing. Deer mice are detected by electronic cables lying on the ground, which register whenever a mouse crosses anywhere along their length. It is supposed that, for a given level of activity, the amount of cable-crossing by mice is proportional to the average density of occupancy along the length of the cables. This should apply regardless of the particular spatial configuration of the cables, whether they are along a single line or concentrated in one area. Such cables effectively exploit the potential advantages of non-capture sampling: (1) The sample size from lines is greater than from discrete points. A mouse can avoid discrete detection points, but it must cross lines if it moves

Obesity and cardiac performance

In association with consistent increases in stroke volume and a high incidence of systemic and/or pulmonary arterial hypertension, the cardiac work of very obese patients at rest was considerably greater than that predicted for normotensive subjects at ideal body weight. Although this change was effected chiefly by increased left ventricular work, and the latter was roughly correlated with the amount of excess body weight, variable increases in right ventricular work resulted in a lack of correlation between total cardiac work and the amount of excess weight. Though pulmonary hypertension secondary to an increase in left ventricular filling pressure usually occurred in the very obese patients of this series under conditions of moderate exercise, the increment in cardiac output per unit increment in oxygen consumption with exercise was within normal limits. Because of the need to move excess body weight, at any given level of activity the cardiac workload was considerably greater for the obese subjects than for individuals at ideal body weight. Cardiac enlargement and increased heart weight were found quite regularly in very obese subjects, increasing in rough proportion to the amount of excess body weight. The increased heart weight was due to muscular hypertrophy involving the left ventricle or both the left and right ventricles. Neither fatty infiltration of the myocardium nor isolated right ventricular hypertrophy was observed. Cardiac failure occurred in 8 per cent of the extremely obese patients in this series, involving a high cardiac output and left ventricular or biventricular insufficiency. It has been proposed that myocardial hypertrophy and failure derive from the increased cardiac workload present at rest and during exercise. Heart failure due to obesity generally responded well to bed rest, digitalis, diuretics, dietary sodium restriction and measures usually effective in managing heart failure due to other causes. Effective long term therapy necessarily involved weight reduction.