4,070 research outputs found
Study of optimal training protocols and devices for developing and maintaining physical fitness in females prior to and during space flight
Pedalling a bicycle at least ten minutes a day at 85% of maximum pulse rate, three days a week for ten weeks will produce moderate increases in overall strength and physical work capacity in college-age females. The longer the training session, up to thirty minutes per session, the greater are the increases in physical work capacity that result when college-age females are trained three days a week for ten weeks at 85% of their maximum heart rate
Isokinetic exercise: A review of the literature
Isokinetic muscle training has all the advantages of isometrics and isotonics while minimizing their deficiencies. By holding the speed of movement constant throughout the full range of motion, isokinetic training devices respond with increased resistance rather than acceleration when the power output of the muscle is increased. Isokinetic training is superior to isometric and isotonic training with respect to increases in strength, specificity of training, desirable changes in motor performance tasks, lack of muscle soreness, and decreases in relative body fat
Special Orders, No. 129: Headquarters of the Army, Adjutant General\u27s Office
Notice of Captain Henry D. Styer being detailed to Utah Agricultural College
Impact-induced acceleration by obstacles
We explore a surprising phenomenon in which an obstruction accelerates,
rather than decelerates, a moving flexible object. It has been claimed that the
right kind of discrete chain falling onto a table falls \emph{faster} than a
free-falling body. We confirm and quantify this effect, reveal its complicated
dependence on angle of incidence, and identify multiple operative mechanisms.
Prior theories for direct impact onto flat surfaces, which involve a single
constitutive parameter, match our data well if we account for a characteristic
delay length that must impinge before the onset of excess acceleration. Our
measurements provide a robust determination of this parameter. This supports
the possibility of modeling such discrete structures as continuous bodies with
a complicated constitutive law of impact that includes angle of incidence as an
input.Comment: small changes and corrections, added reference
The Effect of Land Use and Climate Change on Groundwater Recharge in Gnangara Groundwater System
Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive
Avoiding Biased Clinical Machine Learning Model Performance Estimates in the Presence of Label Selection
When evaluating the performance of clinical machine learning models, one must
consider the deployment population. When the population of patients with
observed labels is only a subset of the deployment population (label
selection), standard model performance estimates on the observed population may
be misleading. In this study we describe three classes of label selection and
simulate five causally distinct scenarios to assess how particular selection
mechanisms bias a suite of commonly reported binary machine learning model
performance metrics. Simulations reveal that when selection is affected by
observed features, naive estimates of model discrimination may be misleading.
When selection is affected by labels, naive estimates of calibration fail to
reflect reality. We borrow traditional weighting estimators from causal
inference literature and find that when selection probabilities are properly
specified, they recover full population estimates. We then tackle the
real-world task of monitoring the performance of deployed machine learning
models whose interactions with clinicians feed-back and affect the selection
mechanism of the labels. We train three machine learning models to flag
low-yield laboratory diagnostics, and simulate their intended consequence of
reducing wasteful laboratory utilization. We find that naive estimates of AUROC
on the observed population undershoot actual performance by up to 20%. Such a
disparity could be large enough to lead to the wrongful termination of a
successful clinical decision support tool. We propose an altered deployment
procedure, one that combines injected randomization with traditional weighted
estimates, and find it recovers true model performance
Hydrochimie des lacs dans la région de Trinidad (Amazonie bolivienne) : influence d'un fleuve andin : le Rio Mamoré
La caractérisation physico-chimique des cours d'eau et des lacs de la région de Trinidad (plaine du Mamoré central) a permis de distinguer deux grands types d'eau. Les eaux d'origine andine (le Rio Mamoré et les lacs qu'il alimente) qui sont relativement bien minéralisées (> 100 mg.l-1), de type bicarbonaté calcique et avec de fortes teneurs relatives en calcium, magnésium et sulfates. Les eaux de la plaine (Rio Mocovi et les lacs peu profonds éloignés du Rio Mamoré) qui sont de type variable, toujours faiblement minéralisées (< 50 mg.l-1), et avec de fortes teneurs relatives en fer et en potassium. L'évolution de l'hydrochimie de ces différents milieux, plus ou moins proches, étudiée au cours de deux cycles hydrologiques, montre une forte influence du Rio Mamoré en période de hautes eaux (de janvier à avril) sur les milieux lacustres adjacents, liée à l'existence de zones d'inondation. (Résumé d'auteur
Datos fisico-quimicos de los medios acuaticos de la zona del Mamoré central : region de Trinidad - Amazonia boliviana
La caractérisation physico-chimique des cours d'eau et des lacs de la région de Trinidad a permis de distinguer deux grands types d'eaux. Les eaux d'origine andine (le rio Mamoré et les lagunes qu'il alimente) qui sont plus minéralisées, de type bicarbonaté calcique, avec de fortes teneurs relatives en calcium, magnésium et sulfates. Les eaux de la plaine (rio Mocovi et les lagunes peu profondes éloignées du rio Mamoré) qui sont de type variable avec de fortes teneurs relatives en fer et potassium. L'évolution de l'hydrochimie de ces milieux, au cours du cycle hydrologique montre une forte influence du rio Mamoré en période de hautes eaux sur le milieu lacustre, liée aux zones d'inondation. (Résumé d'auteur
Reconciling place attachment with catchment-based flood risk management:What can we learn from film?
A catchment-based approach to flood risk management (FRM) is gaining prominence in the United Kingdom. It is undertaken with wider awareness of multiple stakeholders, as part of a catchment scale understanding, and, as with other approaches, can visually re-shape place. Land cover and land management change at this scale also has the potential to reconfigure landscape values and place attachment. Researchers have used qualitative, quantitative, and mapping approaches to understand place attachment. Here we explore secondary data, specifically, we transcribe and code the stories of five Mytholmroyd, West Yorkshire residents from the short film, Calder about the December 26, 2015 floods. We find place attachment, identity, and social capital are interconnected and feature strongly in the mitigation and prevention phase, post-disaster. Our findings suggest better understanding of place attachment can support a more catchment scale approach to FRM policy and practice
Combinatorial optimization applied to VLBI scheduling
Due to the advent of powerful solvers, today linear programming has seen many applications in production and routing. In this publication, we present mixed-integer linear programming as applied to scheduling geodetic very-long-baseline interferometry (VLBI) observations. The approach uses combinatorial optimization and formulates the scheduling task as a mixed-integer linear program. Within this new method, the schedule is considered as an entity containing all possible observations of an observing session at the same time, leading to a global optimum. In our example, the optimum is found by maximizing the sky coverage score. The sky coverage score is computed by a hierarchical partitioning of the local sky above each telescope into a number of cells. Each cell including at least one observation adds a certain gain to the score. The method is computationally expensive and this publication may be ahead of its time for large networks and large numbers of VLBI observations. However, considering that developments of solvers for combinatorial optimization are progressing rapidly and that computers increase in performance, the usefulness of this approach may come up again in some distant future. Nevertheless, readers may be prompted to look into these optimization methods already today seeing that they are available also in the geodetic literature. The validity of the concept and the applicability of the logic are demonstrated by evaluating test schedules for five 1-h, single-baseline Intensive VLBI sessions. Compared to schedules that were produced with the scheduling software sked, the number of observations per session is increased on average by three observations and the simulated precision of UT1-UTC is improved in four out of five cases (6μs average improvement in quadrature). Moreover, a simplified and thus much faster version of the mixed-integer linear program has been developed for modern VLBI Global Observing System telescopes
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