Acoustic spectral analysis and testing techniques

Subjects covered in four reports are described including: (1) mathematical techniques for combining decibel levels of octaves or constant bandwidth: (2) techniques for determining equation for power spectral density function; (3) computer program to analyze acoustical test data; and (4) computer simulation of horn responses utilizing hyperbolic horn theory

Note and Comment

The James McMillan Memorial Association; Liability of Hospitals for the Negligence of Their Physicians and Nurses; Intent in Embezzlement by Corporate Official; The Validity of the Initiative and Referendum; Scope of Review, on Appeal from Decision of State Board of Health, Revoking Certificate to Practice Medicine; What are the Rights of a Person Under a Promise to do That Which He was Already under Obligation to Do?

Note and Comment

American Bar Association Meeting; Disbarment or Suspension of Attorney; Is the Property Owner Negligent if He Fails to Exercise Reasonable Care to Prevent an Injury to An Infant Trespasser?; Liability of Water companies for Losses by Fire; Evidence in Deportation Proceedings Under the Act of congress of May 5th, 1892; Duty of a Bank to a Surety to Apply Funds of a Principal Debtor to Satisfy a Debt Due the Bank

Effect of aerosols and NO₂ concentration on ultraviolet actinic flux near Mexico City during MILAGRO: measurements and model calculations

Urban air pollution absorbs and scatters solar ultraviolet (UV) radiation, and thus has a potentially large effect on tropospheric photochemical rates. We present the first detailed comparison between actinic fluxes (AF) in the wavelength range 330–420 nm measured in highly polluted conditions and simulated with the Tropospheric Ultraviolet-Visible (TUV) model. Measurements were made during the MILAGRO campaign near Mexico City in March 2006, at a ground-based station near Mexico City (the T1 supersite) and from the NSF/NCAR C-130 aircraft. At the surface, measured AF values are typically smaller than the model by up to 25% in the morning, 10% at noon, and 40% in the afternoon, for pollution-free and cloud-free conditions. When measurements of PBL height, NO₂ concentration and aerosols optical properties are included in the model, the agreement improves to within ±10% in the morning and afternoon, and ±3% at noon. Based on daily averages, aerosols account for 68% and NO₂ for 25% of AF reductions observed at the surface. Several overpasses from the C-130 aircraft provided the opportunity to examine the AF perturbations aloft, and also show better agreement with the model when aerosol and NO₂ effects are included above and below the flight altitude. TUV model simulations show that the vertical structure of the actinic flux is sensitive to the choice of the aerosol single scattering albedo (SSA) at UV wavelengths. Typically, aerosols enhance AF above the PBL and reduce AF near the surface. However, for highly scattering aerosols (SSA > 0.95), enhancements can penetrate well into the PBL, while for strongly absorbing aerosols (SSA < 0.6) reductions in AF are computed in the free troposphere as well as in the PBL. Additional measurements of the SSA at these wavelengths are needed to better constrain the effect of aerosols on the vertical structure of the AF

A picture of eight turtles: the child’s understanding of cardinality and numerosity

An essential part of understanding number words (e.g., eight) is understanding that all number words refer to the dimension of experience we call numerosity. Knowledge of this general principle may be separable from knowledge of individual number word meanings. That is, children may learn the meanings of at least a few individual number words before realizing that all number words refer to numerosity. Alternatively, knowledge of this general principle may form relatively early and proceed to guide and constrain the acquisition of individual number word meanings. The current article describes two experiments in which 116 children (2½- to 4-year-olds) were given a Word Extension task as well as a standard Give-N task. Results show that only children who understood the cardinality principle of counting successfully extended number words from one set to another based on numerosity—with evidence that a developing understanding of this concept emerges as children approach the cardinality principle induction. These findings support the view that children do not use a broad understanding of number words to initially connect number words to numerosity but rather make this connection around the time that they figure out the cardinality principle of counting

An evaluation of sit to stand devices for use in rehabilitation

There are many assistive devices to help with raising a person from a seat. These devices are considered active as they require some balance, trunk control and weightbearing ability. There is concern that this movement is mostly passive due to fixation at the trunk and knee. This study explores the movement patterns in sit to stand transfers active and assisted. Study Design: A fully squared repeated measures design was use. All participants (n = 20) used all conditions (n = 7) in a balanced order. Transfers were recorded with; video recordings, a 6 dimensional force plate, hip, knee and ankle positions were recorded with motion capture. Subjective evaluations for comfort and security were completed. Physical data was compared with ANOVA calculations with Bonferroni corrections. Results: Device G scored highest for comfort, knee support and overall preference. Sling movement had a negative effect on the sensations of comfort and security. The motion analysis of the flexible knee support showed: People push into the floor and CoP moved towards the toe.More anterior knee movement (P < 0.05).More bodyweight through feet (P < 0.05).Quicker transfer of weight onto feet.Very low bodyweight was recorded in all lowering actions. The use of a flexible knee support raised the subjective and physical performance of the assistive device and may improve rehabilitation responses

Retrieval of aerosol single scattering albedo at ultraviolet wavelengths at the T1 site during MILAGRO

Surface measurements of direct and diffuse voltages at UV wavelengths were made at the T1 site during the MILAGRO (Megacity Initiative: Local and Global Research Observations) field campaign in March 2006, using a multifilter rotating shadowband radiometer (UV-MFRSR). We used the MFRSR data, together with measurements from a co-located CIMEL Sun photometer at the site operating as part of the AERONET network, to deduce aerosol single scattering albedo (ω) at 368 and 332 nm for four cloud-free days during the study. Our retrievals suggest that T1 aerosols with aerosol extinction optical depth &amp;tau;&lt;sub&gt;368&lt;/sub&gt;&amp;gt;0.1 that are influenced by Mexico City emissions, blowing dust, and biomass burning, are characterized by low &amp;omega;&lt;sub&gt;368&lt;/sub&gt;=0.73–0.85 and &amp;omega;&lt;sub&gt;332&lt;/sub&gt;=0.70–0.86, with small or no spectral variation of ω between 368 and 332 nm. Our findings are consistent with other published estimates of ω for Mexico City aerosols, including those that suggest that the absorption attributable to these aerosols is enhanced at UV wavelengths relative to visible wavelengths. We also demonstrate, via sensitivity tests, the importance of accurate τ and surface albedo measurements in ω retrievals at UV wavelengths

Learning to represent exact numbers

This article focuses on how young children acquire concepts for exact, cardinal numbers (e.g., three, seven, two hundred, etc.). I believe that exact numbers are a conceptual structure that was invented by people, and that most children acquire gradually, over a period of months or years during early childhood. This article reviews studies that explore children’s number knowledge at various points during this acquisition process. Most of these studies were done in my own lab, and assume the theoretical framework proposed by Carey (2009). In this framework, the counting list (‘one,’ ‘two,’ ‘three,’ etc.) and the counting routine (i.e., reciting the list and pointing to objects, one at a time) form a placeholder structure. Over time, the placeholder structure is gradually filled in with meaning to become a conceptual structure that allows the child to represent exact numbers (e.g., There are 24 children in my class, so I need to bring 24 cupcakes for the party.) A number system is a socially shared, structured set of symbols that pose a learning challenge for children. But once children have acquired a number system, it allows them to represent information (i.e., large, exact cardinal values) that they had no way of representing before