Background: Eye movements reveal neurodegenerative disease processes due to overlap between oculomotor circuitry and disease-affected areas. Characterizing oculomotor behaviour in context of cognitive function may enhance disease diagnosis and monitoring. We therefore aimed to quantify cognitive impairment in neurodegenerative disease using saccade behaviour and neuropsychology. Methods: The Ontario Neurodegenerative Disease Research Initiative recruited individuals with neurodegenerative disease: one of Alzheimer’s disease, mild cognitive impairment, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson’s disease, or cerebrovascular disease. Patients (n=450, age 40-87) and healthy controls (n=149, age 42-87) completed a randomly interleaved pro- and anti-saccade task (IPAST) while their eyes were tracked. We explored the relationships of saccade parameters (e.g. task errors, reaction times) to one another and to cognitive domain-specific neuropsychological test scores (e.g. executive function, memory). Results: Task performance worsened with cognitive impairment across multiple diseases. Subsets of saccade parameters were interrelated and also differentially related to neuropsychology-based cognitive domain scores (e.g. antisaccade errors and reaction time associated with executive function). Conclusions: IPAST detects global cognitive impairment across neurodegenerative diseases. Subsets of parameters associate with one another, suggesting disparate underlying circuitry, and with different cognitive domains. This may have implications for use of IPAST as a cognitive screening tool in neurodegenerative disease.

Direct atmospheric 14CO2 measurements began in New Zealand in 1954, initially to improve 14C as a dating tool, but quickly evolving into a method for understanding the carbon cycle. These early 14CO2 measurements immediately demonstrated the existence of an “Atom Bomb Effect,” as well as an “Industrial Effect.” These two gigantic tracer experiments have been utilized via 14CO2 measurements over the years to produce a wealth of knowledge in multiple research fields including atmospheric carbon cycle research, oceanography, soil science, and aging of post-bomb materials.

When engaged on war work as Chief Inspector for Fredk. Sage & Co. at Peterboro’, England, in the spring of 1918, I observed that when Honduras mahogany was compressed across the grain, and parallel, to the annular rings of the wood, a “first” or “natural” elastic limit was reached, after which the deflections increased more rapidly than the load, as has been commonly observed in all testing of all materials.

This paper gives the results of experiments with air-screws having axial motion, the same propellers being tested that were described in the first article (appearing in the AERONAUTICAL JOURNAL for October, 1910): namely, sector-shaped, flat-bladed, true screws having diameters of 1.5, 2, 2.5, 3, and 3.5 feet; also several of 2.5 feet diameter having pitch-coefficients varied from 0.4 to 2.0.

In the light of Laugley's experiments with a whirling-table, I firmly believe that accurate results can only be obtained with .straight line experiments in still air; so, for the purpose of these experiments. I had a track constructed of 30 inch gauge and over 300 feet long, arranged as shown in the profile sketch (Fig. 1). The part A B, 68 feet long, is curved to obtain the initial speed rapidly and without undue length of track ; the remainder, from B to F, was 275 feet long, accurately level and straight. From C to D is 50 ft., and from D to F is 50 ft.; between the points C and E all readings are taken, the portion E to F being simply used to bring the truck gradually to rest. The track from A to E is of iron carefully bonded at the joints to convey electric current from a storage battery; from E to F it is of wood.

In the design of aeroplanes, I have been constantly hampered by lack of reliable formulaæ that would give the thrust and horse-power required for a given diameter, pitch, speed, etc., of screws. The theoretical formulæ are too complex and uncertain for concrete computations, so I have undertaken an experimental study of air screws and have endeavoured to deduce formulæ, from the experimental data, which shall be reliable and at the same time cover the complexities that must enter with screws of widely differing elements such as blade area, form, pitch, etc.

M. S. Drzewiecki, in his excellent theoretical study of Air Screws, says “the question of screws in general is very complex, and poorly enough understood from a theoretical standpoint,” and we might add it is almost equally complex and little understood from the practical and experimental standpoint.

The law, to which I wish to call attention first in this article, can hardly be called unknown, but it has certainly remained unnoticed by the great majority of designers of aeroplanes and other flying machines, and has been generally ignored by scientific writers in aerodynamics, although some of the latter have recognised its existence without apparently seeing its importance ; or, perhaps, although cognizant of its existence, they have been unable to reconcile it with “Langley's law,” and have therefore refrained from giving it the emphasis it undoubtedly deserves.

When we examine the numerous designs that have been proposed for power- driven aëroplanes it is most apparent that the designer, in most cases, has lost sight of the all-important subject of the efficiency of the different parts.

The aeroplanes are often quite large enough to give the required “ lift,” but the “ drift “ is enormous, the propellers are usually far too small in diameter, and the motor is so poorly cooled and adjusted, that it is not capable of giving anything like its rated power.

Any one of these faults is sufficient to make a failure of a possible success, but when they are combined, as they usually are, the machine is hopeless. I have just seen in Paris a machine glaringly wrong even in the most elemental principles, yet the builder had spent a large sum of money for a costly motor and its accessories.

The translocation and root exudation of leaf-applied sublethal concentrations of 14C-labeled clopyralid (3,6-dichloropicolinic acid) and 14C-labeled 2,4-D [(2,4-dichlorophenoxy)acetic acid] were compared in Canada thistle [Cirsium arvense (L.) Scop. var. horridum Wimm. and Grab. ♯ CIRAR] at the rosette stage over a period of 9 days. The rate of absorption and export of 14C out of the treated leaf was similar for both herbicides. However, the distribution of the herbicides throughout the plant was very different. After 9 days, 15 vs. 3% of the applied 14C from 14C-clopyralid vs. 14C-2,4-D, respectively, was isolated from the foliage of the treated leaf. In the roots, twice as much 14C was recovered from the 14C-clopyralid treatments as from the 14C-2,4-D treatment at all sampling times, with 33 vs. 15% being recovered, respectively, after 9 days. When the plants were grown hydroponically, 20% of the 14C-clopyralid vs. 48% of the 14C-2,4-D was recovered in the nutrient solution during a 9-day period. No metabolites of either herbicide were recovered from the foliage, root system, or nutrient solution. Large differences in translocation of these herbicides may account for the unequal toxicity to young Canada thistle plants.

While the North American archaeological record signals the presence of early humans along the northeastern Pacific coast by the Late Pleistocene, we know little about the technological systems employed by these coastally oriented colonizing groups. We here report the discovery of the earliest unequivocal evidence for the use and manufacture of shell fishhooks in the western hemisphere. Four single-piece shell fishhooks dating to the terminal Pleistocene/early Holocene transition (between ~11,300 and 10,700 cal B.P.) have been excavated on Isla Cedros, Baja California, Mexico. One hook is directly dated at 9495 ± 25 B.P. with a marine reservoir–corrected age of 11,165–9185 cal B.P. Radiocarbon ages associated with three other shell fishhooks range between 8900 ± 25 B.P. and 10,415 ± 25 B.P, while median ages for the earliest contexts confirm occupation of the island by at least 12,600–12,000 cal B.P. The stratigraphic levels from which the fishhooks were recovered contained a diverse assemblage of fish remains, including deepwater species, indicative of boat use. Thus, some of the earliest known inhabitants of the Pacific coast of the Americas employed shell hook and line technology for offshore marine fishing at least by the Pleistocene-Holocene transition, if not earlier.

Production systems based on reduced-tillage practices account for over 60% of the cropped land on the Canadian Prairies. Concerns have been expressed regarding potential shifts in weed communities as a result of changing tillage practices. Study objectives were to (1) determine the feasibility of combining and analyzing weed abundance data from 10 medium- to long-term studies on the Canadian Prairies that compared conventional-, reduced-, and zero-tillage systems, (2) identify species that are associated with specific tillage systems, and (3) place species into plant response groups according to the similarity of their tillage system response. Conventional-tillage systems were defined as including both a fall and spring sweep-plow operation before seeding spring crops, whereas reduced tillage consisted of only one sweep-plow operation shortly before seeding. Crops within zero-tillage systems were planted directly into the previous crop's stubble. The association between weed species and tillage systems was investigated using indicator species analysis. Species were assigned to tillage response groups on the basis of the results of the analysis and the expertise of the project scientists. Perennial species such as Canada thistle and perennial sowthistle were associated with reduced- and zero-tillage systems, but annual species were associated with a range of tillage systems. Field pennycress was placed in the conventional-tillage response group, Russian thistle in the zero-tillage group, and wild buckwheat and common lambsquarters were equally abundant in all tillage systems. The goal of classifying weed species based on common functional traits in relation to responses to tillage systems was not realized, in part, because the required information on species biology and ecology was either unavailable or not applicable to local conditions.

We present a study of the energy levels in a FTO/TiO2/CH3NH3PbI3/Spiro solar cell device. The measurements are performed using a novel ambient pressure photoemission (APS) technique alongside Contact Potential Difference data from a Kelvin Probe. The Perovskite Solar Cell energy band diagram is demonstrated for the device in dark conditions and under illumination from a 150W Quartz Tungsten Halogen lamp. This approach provides useful information on the interaction between the different materials in this solar cell device. Additionally, non-destructive macroscopic DC and AC Surface Photovoltage Spectroscopy (SPS) studies are demonstrated of different MAPBI3 device structures to give an indication of overall device performance. AC-SPS measurements, previously used on traditional semiconductors to study the mobility, are used in this case to characterise the ability of a perovskite solar cell device to respond rapidly to chopped light. Two different device structures studied showed very different characteristics: Sample A (without TiO2): (ITO/PEDOT:PSS/polyTPD/CH3NH3PbI3/PCBM) had ∼4 times the magnitude of AC-SPS response compared to Sample B (including TiO2): (ITO/TiO2/ CH3NH3PbI3/Spiro). This demonstrates that the carrier speed characteristics of device architecture A is superior to device architecture B. The TiO2 layer has been associated with carrier trapping which is illustrated in this example. However, the DC-SPV performance of sample B is ∼5 times greater than that of sample A. The band gap of the MAPBI3 layer was determined through DC-SPS (1.57 ± 0.07 eV), Voc of the devices measured and qualitative observations made of interface trapping by DC light pulsing. The combination of these (APS, KP, AC/DC-SPV/SPS) techniques offers a more general method for measuring the energy level alignments and performance of Organic and Hybrid Solar Cell Devices.

Combining atmospheric Δ14CO2 data sets from different networks or laboratories requires secure knowledge on their compatibility. In the present study, we compare Δ14CO2 results from the Heidelberg low-level counting (LLC) laboratory to 12 international accelerator mass spectrometry (AMS) laboratories using distributed aliquots of five pure CO2 samples. The averaged result of the LLC laboratory has a measurement bias of –0.3±0.5‰ with respect to the consensus value of the AMS laboratories for the investigated atmospheric Δ14C range of 9.6 to 40.4‰. Thus, the LLC measurements on average are not significantly different from the AMS laboratories, and the most likely measurement bias is smaller than the World Meteorological Organization (WMO) interlaboratory compatibility goal for Δ14CO2 of 0.5‰. The number of intercomparison samples was, however, too small to determine whether the measurement biases of the individual AMS laboratories fulfilled the WMO goal.

Confusion has arisen regarding just what is meant by adjustable variablepitch and controllable-pitch propellers, and the matter should Be more clearly defined in the following way:—Fixed-pitch propellers to apply to both (a) the ordinary fixed-pitch propeller, made up with the hub and blades integral, and the material the same throughout, and (b) the detachable-blade or ground-adjustable type that will usually have the hub and blades of different materials, and in which the blades will be clamped in the hubs on the ground to an angle that is assumed, usually by experiment, to give the best general or some specially desired performance results.