Evaluation of Pit-trap Transects With Varied Trap Spacing in a Northern Michigan Forest

The study compared effects of four distances between traps (range 0.5-4.0 m) on arthropod captures. Twelve traps were aligned in each of four transects, and 20 samples. trap were obtained during summer and fall in a northern Michigan deciduous forest. Catches proved to be unaffected by trap spacing. Rather, they reflected local within-site differences in abundance of dominant species

The Life Cycle Relative to Temperature of Protaphorura Armatus (Tullberg) (Collembola: Onychiuridae), a Parathenogenetic Species

Apparent parthenogenetic reproduction in Collembola has sometimes been attributed to accidental transfer of spermatophores with the food material from one culture to another (Schaller, 1953; Mayer, 1957). Conclusive evidence of parthenogenesis has only in recent years been accumulated for a number of species of Collembola, of which some were found in field populations consisting entirely of females (Choudhuri, 1958; Huther, 1961; Marshall and Kevan, 1962; Petersen, 1965; 1971 ; Snider, 1973). In Onychiuridae, parthenogenesis is apparently quite common. Onychiurus parthenogeneticus Choudhuri and Tullbergia krausbaueri (Bomer) undoubtedly reproduce in the absence of males (Choudhuri, 1958; Hale, 1966; Petersen, 1971); so does Tullbergia granulata Mills, where individuals reared in isolation from the time of hatching invariably lay viable eggs (unpublished observations). Large females of Onychiurus procampatus Gisin 1956 breed through a form of thelytokous parthenogenesis (Hale, 1964). The size groupings found in O. procarnpatus (two sizes of females and only small males) were also observed in O. firnatus Gisin 1952 and O. quadriocellatus Gisin 1947 and may indicate the existence of both parthenogenetic and sexually reproducing forms in these species (Hale, 1964). Recent laboratory observations on Protaphorura armatus (Tullberg) revealed that this species too reproduces parthenogenetically. The present study was undertaken to investigate the effect of temperature on the biology of the species

Influence of Exercise Environment on Stress and Affect in Sedentary Adults: A Comparison of Indoor and Natural Environments

The national need for increased physical activity, especially among sedentary populations, has been well documented. The need now is for fitness programs to be more effective at encouraging individuals to adopt and maintain a physically active lifestyle. This study investigated the relationship between exercise environment, stress, affect, and Nature Relatedness. Because stress reduction has been seen as a benefit of being exposed to nature, stress and affect were assessed in sedentary adults at the beginning and end of short walks in an outdoor and indoor environment in an effort to determine which environment had the greater ability to reduce stress. Stress and affect were measured using salivary cortisol concentration and alpha-amylase activity, as well as surveys and questionnaires. Additionally, the link between Nature Relatedness and environmental preference was assessed. Ultimately, our results indicated that this population expressed a preference for exercising in the outdoor environment over the indoor environment

The Life History of Folsomia Candida (Willem) (Collembola: Isotomidae) Relative to Temperature

The parthenogenetic mode of reproduction in Collembola, although frequently questioned in the past (Schaller, 1953; Mayer, 1957; Falkenhan, 1932), has only recently been recorded and confirmed for several species; Onychiutus parthenogeneticus Choudhuri (Choudhuri, 1958), Folsomia candida (Willem) (Goto, 1960; Marshall and Kevan, 1962; Green, 1964; Husson and Paldvody, 1967), Folsomia cavicola Cassagnau and Delamare (Goto, 1960), Tullbergia krausbaueri (Bomer) (Hale, 1966; Petersen, 1971), and Isotoma notabilis Schaffer (Petersen, 1971). Sex-ratios in populations of the above cited species are often unknown. Existing data indicate that the composition of a population may vary with the geographical distribution of the species. Populations of Folsomia candida (Willem), known to be bisexual in England (Goto, 1960), have been found so far to consist entirely of females in Canada (Sharma and Kevan, 1963a) and in Michigan (Snider, 1973). Similar to I. notabilis and T. krausbaueri (Petersen, 1971), investigations throughout the year and over larger geographic areas are necessary before northern USA and Canada F. candida may be labeled as obligatory parthenogenetic. Snider (1973) recorded in detail the life cycle of F. candida at 21°C. The present study provides information on the influence of temperature on the bionomics of the species

Observations of attenuation at 20.6, 31.65 and 90.0 GHz: Preliminary results from Wallops Island, VA

Ground based radiometric observations of atmospheric attenuation at 20.6, 31.65, and 90.0 GHz were made at Wallops Island, Virginia during April and May 1989. Early results from the analysis of the data set are compared with previous observations from California and Colorado. The relative attenuation ratios observed at each frequency during clear, cloudy, and rainy conditions are shown. Plans for complete analysis of the data are described

Optical particle counter measurement of marine aerosol hygroscopic growth

International audienceA technique is developed for the determination of the hygroscopic growth factor of dry particles with diameter between 0.3 and 0.6 ?m and is applied to measurements made during the second Dynamics and Chemistry of Marine Stratocumulus experiment (DYCOMS-II). Two optical particle counters are utilized, one measures the aerosol size spectrum at ambient relative humidity and the other simultaneously dries the aerosol prior to light scattering detection. Growth factors are based on measurements made in the region of the Mie scattering curve where scattered light intensity increases monotonically with dry and wet particle diameter, i.e. D<0.9 ?m. Factors influencing the accuracy of the measurement are evaluated, including particle drying, refractive index and shape. Growth factors at 90±3% ambient relative humidity in marine airmasses 400 km west of San Diego, California range between 1.5 and 1.8. This suggests that a significant fraction of the particle mass, between 40 and 70%, is either non-hygroscopic or weakly hygroscopic

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Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108083/1/hep26952.pd

A spin field effect transistor for low leakage current

In a spin field effect transistor, a magnetic field is inevitably present in the channel because of the ferromagnetic source and drain contacts. This field causes random unwanted spin precession when carriers interact with non-magnetic impurities. The randomized spins lead to a large leakage current when the transistor is in the ``off''-state, resulting in significant standby power dissipation. We can counter this effect of the magnetic field by engineering the Dresselhaus spin-orbit interaction in the channel with a backgate. For realistic device parameters, a nearly perfect cancellation is possible, which should result in a low leakage current.Comment: To appear in Physica E. The revised version has additional material which addresses the issue of which way the contacts should be magnetized in a Spin Field Effect Transistor. This was neither addressed in the previous version, nor in the upcoming journal pape

Aircraft/island/ship/satellite intercomparison: Preliminary results from July 16, 1987

The First ISCCP Regional Experiment (FIRE) objective of validating and improving satellite algorithms for inferring cloud properties from satellite radiances was one of the central motivating factors in the design of the specific field experimental strategies used in the July, 1987 marine stratocumulus intensive field observations (IFO). The in situ measuring platforms were deployed to take maximum advantage of redundant measurements (for intercomparison of the in situ sensors) and to provide optimal coverage within satellite images. One of the most ambitious of these strategies was the attempt to coordinate measurements from San Nicolas Island (SNI), the R/V Pt. Sur, the meteorological aircraft, and the satellites. For the most part, this attempt was frustrated by flight restrictions in the vicinity of SNI. The exception was the mission of July 16, 1987, which achieved remarkable success in the coordination of the platforms. This presentation concerns operations conducted by the National Center for Atmospheric Research (NCAR) Electra and how data from the Electra can be integrated with and compared to data from the Pt. Sur, SNI, and the satellites. The focus is on the large-scale, integrated picture of the conditions on July 16 from the perspective of the Electra's flight operations

Reservoir Computing Approach to Robust Computation using Unreliable Nanoscale Networks

As we approach the physical limits of CMOS technology, advances in materials science and nanotechnology are making available a variety of unconventional computing substrates that can potentially replace top-down-designed silicon-based computing devices. Inherent stochasticity in the fabrication process and nanometer scale of these substrates inevitably lead to design variations, defects, faults, and noise in the resulting devices. A key challenge is how to harness such devices to perform robust computation. We propose reservoir computing as a solution. In reservoir computing, computation takes place by translating the dynamics of an excited medium, called a reservoir, into a desired output. This approach eliminates the need for external control and redundancy, and the programming is done using a closed-form regression problem on the output, which also allows concurrent programming using a single device. Using a theoretical model, we show that both regular and irregular reservoirs are intrinsically robust to structural noise as they perform computation