3,703 research outputs found
Renormalization of Higher Derivative Operators in the Matrix Model
-theory is believed to be described in various dimensions by large
field theories. It has been further conjectured that at finite , these
theories describe the discrete light cone quantization (DLCQ) of theory.
Even at low energies, this is not necessarily the same thing as the DLCQ of
supergravity. It is believed that this is only the case for quantities which
are protected by non-renormalization theorems. In 0+1 and 1+1 dimensions, we
provide further evidence of a non-renormalization theorem for the terms,
but also give evidence that there are not such theorems at order and
higher.Comment: 14 pages latex. Note added in light of recent development
Self-Efficacy and Post-Secondary First-Term Student Achievement
Generalized self-efficacy is the overall belief in one’s ability and Specific self-efficacy is task related. The study examined the extent and manner in which self-efficacy explains variation in first-term GPA. The General Self-Efficacy Scale was adapted and used with a sample of N = 194 students (34% male and 66% female) enrolled in a for-profit career education urban college. The data from two factors derived using an exploratory factor analysis, General self-efficacy and Specific self-efficacy, had alpha reliabilities of .73 and .75, respectively. General self-efficacy was correlated r = .18 with GPA and multiple regression analysis demonstrated that General incremented the explanation of variance 5% in GPA (p \u3c .01). Specific correlated r = .17 with GPA (p \u3c .05). General and Specific were significantly correlated (r = .42, p \u3c .001). The two independent variables were equal predictors of success
The Relationship of Self-Efficacy with GPA, Attendance, and College Student Retention
The purpose of this study was to examine the relationship between self-efficacy or belief in one’s capability (Bandura 1977b, 1986, 1993, 1997) and first-term GPA, attendance, and retention using a modified version of the General Self-Efficacy Scale (GSE) (Schwarzer, 1992, 1993, 2005; Schwarzer & Jerusalem, 1993).
The study “College” is part of one of the world’s largest for-profit career education organizations. At the College, 100% of the students commute to classes and live in the metropolitan area. A large percentage of students live in difficult urban neighborhoods and grow up with low family income, abuse, gang violence, drugs, health problems, poor English, and academic underachievement.
A study of student responsibility indicated that 54% of community college students are under the age of 25 and are not prepared academically or psychologically for what will be expected (Howell, 2001). They work to support dependents, frequently require childcare assistance, question their academic ability and perceive teachers as experts who dispense information and wisdom, and are frequently first-generation students.
First-term student success at the College is measured by academic achievement (a required minimum GPA of 1.5 on a scale of 0 to 4.0). Many students receive formal academic warnings at the end of their first term because of poor academic performance in terms of GPA (1.5-2.0) or are involuntarily withdrawn for a GPA less than 1.5.
The College has an open-admissions policy. Only a high school diploma or a GED is required for entry. Admissions representatives have a quota of students to recruit each term. Consequently, admission standards are flexible, as would be expected in a for-profit college. In this business context, being able to predict those students likely to earn a GPA of 1.5, consistently attend classes, and return for the next term translates into institutional success because continuing students generate future cash flow and profitability. The educational issue is being able to identify those students who need academic support to succeed. The purpose of this study was to determine if the construct of self-efficacy (Bandura 1977b, 1986, 1993, 1997) can predict student success and identify “at risk” students at the start of their first term at the College
The Proper Motion of the Central Compact Object RX J0822-4300 in the Supernova Remnant Puppis A
Using the High Resolution Camera (HRC) aboard the Chandra X-ray Observatory,
we have re-examined the proper motion of the central compact object RX
J0822-4300 in the supernova remnant Puppis A. New data from 2010 August,
combined with three archival data sets from as early as 1999 December, provide
a baseline of 3886 days (more than 10 1/2 years) to perform the measurement.
Correlating the four positions of RX J0822-4300 measured in each data set
implies a projected proper motion of mu 71 \pm 12 masy. For a distance of 2 kpc
this proper motion is equivalent to a recoil velocity of 672 \pm 115 km/s. The
position angle is found to be 244 \pm 11 degrees. Both the magnitude and
direction of the proper motion are in agreement with RX J0822-4300 originating
near the optical expansion center of the supernova remnant. For a displacement
of 371 \pm 31 arcsec between its birth place and today's position we deduce an
age of (5.2 \pm 1.0) 10^3 yrs for RX J0822-4300. The age inferred from the
neutron star proper motion and filament motions can be considered as two
independent measurements of the same quantity. They average to 4450 \pm 750 yrs
for the age of the supernova remnant Puppis A.Comment: Accepted for publication in the Astrophysical Journa
Comment on Multigraviton Scattering in the Matrix Model
We show by explicit calculation that the matrix model effective action does
not contain the term , in the limit , contradicting a result reported recently.Comment: LaTex, 10 pages. Note added and minor correction
Reconfigurable antenna pattern verification
A method of verifying programmable antenna configurations is disclosed. The method comprises selecting a desired antenna configuration from a plurality of antenna configuration patterns, with the selected antenna configuration forming at least one reconfigurable antenna from reconfigurable antenna array elements. The method validates the formation of the selected antenna configuration to determine antenna performance of the at least one reconfigurable antenna
Structural Evidence of a Major Conformational Change Triggered by Substrate Binding in DapE Enzymes: Impact on the Catalytic Mechanism
The X-ray crystal structure of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase from Haemophilus influenzae (HiDapE) bound by the products of hydrolysis, succinic acid and l,l-DAP, was determined at 1.95 Å. Surprisingly, the structure bound to the products revealed that HiDapE undergoes a significant conformational change in which the catalytic domain rotates ∼50° and shifts ∼10.1 Å (as measured at the position of the Zn atoms) relative to the dimerization domain. This heretofore unobserved closed conformation revealed significant movements within the catalytic domain compared to that of wild-type HiDapE, which results in effectively closing off access to the dinuclear Zn(II) active site with the succinate carboxylate moiety bridging the dinculear Zn(II) cluster in a μ-1,3 fashion forming a bis(μ-carboxylato)dizinc(II) core with a Zn–Zn distance of 3.8 Å. Surprisingly, His194.B, which is located on the dimerization domain of the opposing chain ∼10.1 Å from the dinuclear Zn(II) active site, forms a hydrogen bond (2.9 Å) with the oxygen atom of succinic acid bound to Zn2, forming an oxyanion hole. As the closed structure forms upon substrate binding, the movement of His194.B by more than ∼10 Å is critical, based on site-directed mutagenesis data, for activation of the scissile carbonyl carbon of the substrate for nucleophilic attack by a hydroxide nucleophile. Employing the HiDapE product-bound structure as the starting point, a reverse engineering approach called product-based transition-state modeling provided structural models for each major catalytic step. These data provide insight into the catalytic reaction mechanism and also the future design of new, potent inhibitors of DapE enzymes
The Gravitational Lens Candidate FBQ 1633+3134
We present our ground-based optical imaging, spectral analysis, and high
resolution radio mapping of the gravitational lens candidate FBQ 1633+3134.
This z=1.52, B=17.7 quasar appears double on CCD images with an image
separation of 0.66 arcseconds and a flux ratio of ~3:1 across BVRI filters. A
single 0.27 mJy radio source is detected at 8.46 GHz, coincident to within an
arcsecond of both optical components, but no companion at radio wavelengths is
detected down to a flux level of 0.1 mJy (3 sigma). Spectral observations
reveal a rich metal-line absorption system consisting of a strong Mg II doublet
and associated Fe I and Fe II absorption features, all at an intervening
redshift of z=0.684, suggestive of a lensing galaxy. Point spread function
subtraction however shows no obvious signs of a third object between the two
quasar images, and places a detection limit of I > 23.0 if such an object
exists. Although the possibility that FBQ 1633+3134 is a binary quasar cannot
be ruled out, the evidence is consistent with it being a single quasar lensed
by a faint, metal-rich galaxy.Comment: 24 pages, 5 figures. Accepted by AJ. A calibration error affecting B
and V band apparent magnitudes has been corrected. The conclusions of the
paper are not change
Antenna reconfiguration verification and validation
A method of testing the electrical functionality of an optically controlled switch in a reconfigurable antenna is provided. The method includes configuring one or more conductive paths between one or more feed points and one or more test point with switches in the reconfigurable antenna. Applying one or more test signals to the one or more feed points. Monitoring the one or more test points in response to the one or more test signals and determining the functionality of the switch based upon the monitoring of the one or more test points
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