Intermittent long-wavelength red light increases the period of daily locomotor activity in mice

BACKGROUND: We observed that a dim, red light-emitting diode (LED) triggered by activity increased the circadian periods of lab mice compared to constant darkness. It is known that the circadian period of rats increases when vigorous wheel-running triggers full-spectrum lighting; however, spectral sensitivity of photoreceptors in mice suggests little or no response to red light. Thus, we decided to test the following hypotheses: dim red light illumination triggered by activity (LEDfb) increases the circadian period of mice compared to constant dark (DD); covering the LED prevents the effect on period; and DBA2/J mice have a different response to LEDfb than C57BL6/J mice. METHODS: The irradiance spectra of the LEDs were determined by spectrophotometer. Locomotor activity of C57BL/6J and DBA/2J mice was monitored by passive-infrared sensors and circadian period was calculated from the last 10 days under each light condition. For constant dark (DD), LEDs were switched off. For LED feedback (LEDfb), the red LED came on when the mouse was active and switched off seconds after activity stopped. For taped LED the red LED was switched on but covered with black tape. Single and multifactorial ANOVAs and post-hoc t-tests were done. RESULTS: The circadian period of mice was longer under LEDfb than under DD. Blocking the light eliminated the effect. There was no difference in period change in response to LEDfb between C57BL/6 and DBA/2 mice. CONCLUSION: An increase in mouse circadian period due to dim far-red light (1 lux at 652 nm) exposure was unexpected. Since blocking the light stopped the response, sound from the sensor's electronics was not the impetus of the response. The results suggest that red light as background illumination should be avoided, and indicator diodes on passive infrared motion sensors should be switched off

Crystallization and preliminary X-ray diffraction studies of UP1, the two-RRM domain of hnRNP A1

The N-terminal domain of hnRNP A1 protein, termed UP1, comprises two tandem RNA-recognition motifs, both of which are necessary for efficient RNA binding and for the alternative splicing activity of hnRNP A1. Recombinant human UP1 expressed in E. coli has been crystallized in space group P2(1) with unit-cell dimensions a = 37.94, b = 43.98, c = 55.64 Angstrom and beta = 93.9 degrees. The unit-cell volume is consistent with one UP1 molecule per asymmetric unit and a calculated 49% solvent content. The crystal diffraction limit is higher than 1.3 Angstrom, and a data set to 2.0 Angstrom has been collected. Diffraction data from one platinum and two mercury derivatives have also been collected

General splicing factor SF2/ASF promotes alternative splicing by binding to an exonic splicing enhancer

The general splicing factor SF2/ASF binds in a sequence-specific manner to a purine-rich exonic splicing enhancer (ESE) in the last exon of bovine growth hormone (bGH) pre-mRNA. More importantly, SF2/ASF stimulates in vitro splicing of bGH intron D through specific interaction with the ESE sequences. However, another general splicing factor, SC35, does not bind the ESE sequences and has no effect on bGH intron D splicing. Thus, one possible function of SF2/ASF in alternative and, perhaps, constitutive pre-mRNA splicing is to recognize ESE sequences. The stimulation of bGH intron D splicing by SF2/ASF is counteracted by the addition of hnRNP A1. The relative levels of SF2/ASF and hnRNP A1 influence the efficiency of bGH intron D splicing in vitro and may be the underlying mechanism of this alternative pre-mRNA processing event in vivo

RNA splicing at human immunodeficiency virus type 1 3 ' splice site A2 is regulated by binding of hnRNP A/B proteins to an exonic splicing silencer element

The synthesis of human immunodeficiency virus type 1 (HIV-1) mRNAs is a complex process by which more than 30 different mRNA species are produced by alternative splicing of a single primary RNA transcript. HIV-1 splice sites are used with significantly different efficiencies, resulting in different levels of mRNA species in infected cells. Splicing of Tat mRNA, which is present at relatively low levels in infected cells, is repressed by the presence of exonic splicing silencers (ESS) within the two tat coding exons (ESS2 and ESS3). These ESS elements contain the consensus sequence PyUAG. Here we show that the efficiency of splicing at 3 ' splice site A2, which is used to generate Vpr mRNA, is also regulated by the presence of an ESS (ESSV), which has sequence homology to ESS2 and ESS3. Mutagenesis of the three PyUAG motifs within ESSV increases splicing at splice site A2, resulting in increased Vpr mRNA levels and reduced skipping of the noncoding exon flanked by A2 and D3. The increase in Vpr mRNA levels and the reduced skipping also occur when splice site D3 is mutated toward the consensus sequence. By in vitro splicing assays, we show that ESSV represses splicing when placed downstream of a heterologous splice site. A1, A1(B), A2, and B1 hnRNPs preferentially bind to ESSV RNA compared to ESSV mutant RNA. Each of these proteins, when added back to HeLa cell nuclear extracts depleted of ESSV-binding factors, is able to restore splicing repression. The results suggest that coordinate repression of HIV-1 RNA splicing is mediated by members of the hnRNP A/B protein family

The CR chondrite clan

The (1) CR chondrites, (2) LEW 85332,(3) Acfer 182,(4) ALH 85085-like chondrites, and (5) Bencubbin-like chondritic breccias are five kinds of chondritic groups which have dramatically different petrographic characteristics, but have mineralogical, bulk chemical, and oxygen and nitrogen isotopic similarities that indicate they are closely related. They are all considered to be members of what we term the CR chondrite clan. Distinguishing characteristics of CR clan chondrites include : (a) reduced, Mg-rich mafic silicates, (b) hydrous matrix and/or dark inclusions (except for Bencubbin-like chondrites), (c) high modal abundances of FeNi metal, (d) FeNi metal having a solar Ni : Co ratio, (e) solar (CI) abundances of refractory and moderately volatile lithophiles, and highly depleted abundances of volatile lithophiles, (f) similar oxygen isotopic compositions of whole rocks, chondrules and matrices, which are on or near the CR mixing line, and (g) anomalously high ^N abundances. CR clan chondrites must have formed in the same local region of the nebula, from closely related reservoirs of materials. The coexistence of anhydrous chondrules with hydrous matrix (and dark inclusions) in the LEW 85332,Acfer 182,and ALH 85085-like chondrites, as well as the widely differing degrees of hydration within and between chondritic samples, implies that hydration of the components was not variable in a single locality, but took place at a variety of locales prior to final lithification of the CR clan chondrites

Identifying the Independent Inertial Parameter Space of Robot Manipulators

This paper presents a new approach to the problem of finding the minimum number of inertial parameters of robot manipulator dynamic equations of motion. Based upon the energy difference equation, it is equally applica ble to serial link manipulators as well as graph structured manipulators. The method is conceptually simple, compu tationally efficient, and easy to implement. In particular, the manipulator kinematics and the joint positions and velocities are the only inputs to the algorithm. Applica tions to a serial link and a graph structured manipulator are illustrated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67982/2/10.1177_027836499101000606.pd

Do chiropractic college faculty understand informed consent: a pilot study

BACKGROUND: The purpose of this study was to survey full-time faculty at a single chiropractic college concerning their knowledge of Institutional Review Board (IRB) policies in their institution as they pertain to educational research. METHODS: All full-time faculty were invited to participate in an anonymous survey. Four scenarios involving educational research were described and respondents were asked to select from three possible courses of action for each. In addition, respondents were queried about their knowledge of IRB policies, how they learned of these policies and about their years of service and departmental assignments. RESULTS: The response rate was 55%. In no scenario did the level of correct answers by all respondents score higher than 41% and in most, the scores were closer to just under 1 in 3. Sixty-five percent of respondents indicated they were unsure whether Palmer had any policies in place at all, while 4% felt that no such policies were in place. Just over one-quarter (27%) were correct in noting that students can decline consent, while more than half (54%) did not know whether there were any procedures governing student consent. CONCLUSION: Palmer faculty have only modest understanding about institutional policies regarding the IRB and human subject research, especially pertaining to educational research. The institution needs to develop methods to provide knowledge and training to faculty. The results from this pilot study will be instrumental in developing better protocols for a study designed to survey the entire chiropractic academic community

SEISMIC SOURCE SCALING AND DISCRIMINATION IN DIVERSE TECTONIC ENVIRONMENTS

The objectives of this study are to improve low-magnitude regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the MDAC (Magnitude and Distance Amplitude Corrections) method to empirically account for these effects through regional calibration. The accuracy of these corrections has a direct impact on our ability to identify clandestine explosions in the broad regional areas characterized by low seismicity. Unfortunately our knowledge of source scaling at small magnitudes (i.e., m{sub b} < {approx}4.0) is poorly resolved. It is not clear whether different studies obtain contradictory results because they analyze different earthquakes, or because they use different methods. Even in regions that are well studied, such as test sites or areas of high seismicity, we still rely on empirical scaling relations derived from studies taken from half-way around the world at inter-plate regions. We investigate earthquake sources and scaling from different tectonic settings, comparing direct and coda wave analysis methods. We begin by developing and improving the two different methods, and then in future years we will apply them both to each set of earthquakes. Analysis of locally recorded, direct waves from events is intuitively the simplest way of obtaining accurate source parameters, as these waves have been least affected by travel through the earth. But there are only a limited number of earthquakes that are recorded locally, by sufficient stations to give good azimuthal coverage, and have very closely located smaller earthquakes that can be used as an empirical Green's function (EGF) to remove path effects. In contrast, coda waves average radiation from all directions so single-station records should be adequate, and previous work suggests that the requirements for the EGF event are much less stringent. We can study more earthquakes using the coda-wave methods, while using direct wave methods for the best recorded subset of events so as to investigate any differences between the results of the two approaches. Finding 'perfect' EGF events for direct wave analysis is difficult, as is ascertaining the quality of a particular EGF event. We develop a multi-taper method to obtain time-domain source-time-functions by frequency division. If an earthquake and EGF event pair are able to produce a clear, time-domain source pulse then we accept the EGF event. We then model the spectral (amplitude) ratio to determine source parameters from both direct P and S waves. We use the well-recorded sequence of aftershocks of the M5 Au Sable Forks, NY, earthquake to test the method and also to obtain some of the first accurate source parameters for small earthquakes in eastern North America. We find that the stress drops are high, confirming previous work suggesting that intraplate continental earthquakes have higher stress drops than events at plate boundaries. We simplify and improve the coda wave analysis method by calculating spectral ratios between different sized earthquakes. We first compare spectral ratio performance between local and near-regional S and coda waves in the San Francisco Bay region for moderate-sized events. The average spectral ratio standard deviations using coda are {approx}0.05 to 0.12, roughly a factor of 3 smaller than direct S-waves for 0.2 < f < 15.0 Hz. Also, direct wave analysis requires collocated pairs of earthquakes whereas the event-pairs (Green's function and target events) can be separated by {approx}25 km for coda amplitudes without any appreciable degradation. We then apply coda spectral ratio method to the 1999 Hector Mine mainshock (M{sub w} 7.0, Mojave Desert) and its larger aftershocks. We observe a clear departure from self-similarity, consistent with previous studies using similar regional datasets

Strong Structural Controllability and Zero Forcing

In this chapter, we study controllability and output controllability of systems defined over graphs. Specifically, we consider a family of state-space systems, where the state matrix of each system has a zero/non-zero structure that is determined by a given directed graph. Within this setup, we investigate under which conditions all systems in this family are controllable, a property referred to as strong structural controllability. Moreover, we are interested in conditions for strong structural output controllability. We will show that the graph-theoretic concept of zero forcing is instrumental in these problems. In particular, as our first contribution, we prove necessary and sufficient conditions for strong structural controllability in terms of so-called zero forcing sets. Second, we show that zero forcing sets can also be used to state both a necessary and a sufficient condition for strong structural output controllability. In addition to these main results, we include interesting results on the controllability of subfamilies of systems and on the problem of leader selection.</p