The energy sector is changing fast, but is it enough to keep global warming within 2ºC?

Seb Henbest writes that 64 percent of global installed capacity will produce zero emissions by 2040

Formation of a Proto-Quasar from Accretion Flows in a Halo

We present a detailed model for the formation of massive objects at the centers of galaxies. The effects of supernovae heating and the conditions of gas loss are revisited. The escape time of the gas is compared with the cooling time, which provides an additional condition not previously considered. Its consequences for the allowed mass range of the halo is calculated. It is shown that sufficient gas is retained to form massive dark objects and quasars even for moderately massive halos but a decline is expected at low redshifts. Subsequently, a gaseous disk forms with a radial extent of a ~kpc, spun up by tidal torques and magnetized by supernovae fields with fields strengths of $10-100 \mu G$. In a model of a self-similar accretion flow in an initially dominant halo, it is shown that for typical halo parameters, about $10^8 M_\odot$ accretes via small magnetic stresses (or alternatively by self-gravity induced instability or by alpha viscosity) in $10^8$ years into a compact region. A model of a self-gravitating evolution of a compact magnetized disk, which is relevant when a significant fraction of the disk mass falls in, is presented, and it has a rapid collapse time scale of a million years. The two disk solutions, one for accretion in an imposed halo potential and the other for self-gravitating disk, obtained here, have general utility and can be adapted to other contexts like protostellar disks as well.Comment: 15 pages, 6 Figures, In Press in Astronomy & Astrophysic

Stereoselective synthesis of hydroxylated 3-aminoazepanes using a multi-bond forming, three-step tandem process

A multi-bond forming, three-step tandem process involving a palladium(II)-catalysed Overman rearrangement and a ring closing metathesis reaction has been utilised for the efficient synthesis of a 2,3,6,7-tetrahydro-3-amidoazepine. Substrate directed epoxidation or dihydroxylation of this synthetic intermediate has allowed the diastereoselective synthesis of hydroxylated 3-aminoazepanes including the syn-diastereomer of the balanol core. Asymmetric synthesis of the 2,3,6,7-tetrahydro-3-amidoazepine motif was also achieved using a chiral palladium(II)-catalyst during the Overman rearrangement

The Impact of the COVID-19 Pandemic on Depression and Anxiety Among Idaho Adults

Research indicates that the COVID-19 pandemic had negative repercussions on the mental health of U.S. citizens. The purpose of this study was to explore the impact the COVID-19 pandemic had on depression and anxiety on a population aged 18 years and older. Using a quantitative correlational repeated design, archival data were analyzed to evaluate the change in depression (as measured using the Patient Health Questionnaire-9) and anxiety (as measured using the Generalized Anxiety Disorder-7 [GAD-7]) indices from a non-pandemic year (2019) to the 1st pandemic year (2020) among patients of an outpatient community health care center. The study took into account age, sex, income level, and historical depression and anxiety diagnoses. Data were analyzed using t and chi-square tests. Results showed that depression and anxiety scores were reduced during COVID compared to the pre-COVID baseline. In addition, men had less depression and anxiety than women overall. Women who were diagnosed with major depressive disorder (MDD) were younger (M = 47 years old) compared to women who were not diagnosed with MDD. However, men with MDD were older (M = 49 years old) compared to men without MDD (M = 47 years old). There was no statistical difference in age and anxiety between men and women. Income and MDD or GAD were not statistically significant, which may be due to the small sample size of participants who reported income. This study demonstrated the importance of positive social change through routine screening in provider offices, ongoing support during mental health treatment, and better mental health for patients under the care of a provider

Considering the Case for Biodiversity Cycles: Reexamining the Evidence for Periodicity in the Fossil Record

Medvedev and Melott (2007) have suggested that periodicity in fossil biodiversity may be induced by cosmic rays which vary as the Solar System oscillates normal to the galactic disk. We re-examine the evidence for a 62 million year (Myr) periodicity in biodiversity throughout the Phanerozoic history of animal life reported by Rohde & Mueller (2005), as well as related questions of periodicity in origination and extinction. We find that the signal is robust against variations in methods of analysis, and is based on fluctuations in the Paleozoic and a substantial part of the Mesozoic. Examination of origination and extinction is somewhat ambiguous, with results depending upon procedure. Origination and extinction intensity as defined by RM may be affected by an artifact at 27 Myr in the duration of stratigraphic intervals. Nevertheless, when a procedure free of this artifact is implemented, the 27 Myr periodicity appears in origination, suggesting that the artifact may ultimately be based on a signal in the data. A 62 Myr feature appears in extinction, when this same procedure is used. We conclude that evidence for a periodicity at 62 Myr is robust, and evidence for periodicity at approximately 27 Myr is also present, albeit more ambiguous.Comment: Minor modifications to reflect final published versio

Orthodontic bracket bond strength and resin composite adhesive degree of conversion associated with type of curing unit and total energy

Title from PDF of title page, viewed on March 27, 2014Thesis advisor: Mary P. WalkerVitaIncludes bibliographical references (pages 45-51)Thesis (M. S.)--School of Dentistry. University of Missouri--Kansas City, 2013This study examined the effect of light curing sources on shear bond strength and degree of conversion of orthodontic resin composite adhesive as function of type of curing unit and total energy, as well as evaluated the correlation between shear bond strength and degree of conversion. Curing units included in the study were plasma arc (PA), light emitting diode (LED) and quartz tungsten halogen (QTH) with 5k, 10k, or 15k mJ/cm2 of total energy delivered to the orthodontic adhesive by each unit type. Based on an analysis of variance (α=.05), there was no significant effect of type of curing source on shear bond strength; however, there was a significant effect of total energy, with shear bond strength encreasing as energy increased across curing units. For degree of conversion there was a significant effect of curing unit with PA producing higher degree of conversion than LED or QTH, which were not significantly different from each other. There was also a significant effect of total energy on degree of conversion with a significant increase between 5k to 10k mJ/cm2. There was a positive moderate overall correlation between shear bond strength and degree of conversion. Results of this study suggest that the PA curing unit is more efficient at polymerization (degree of conversion) of orthodontic resin composite adhesive. However, there is no difference in shear bond strength produced when using PA, LED or QTH curing sources for orthodontic bracket bonding procedures when equal total energy is delivered to the adhesiveAbstract -- List of illustrations -- List of tables -- Acknowledgments -- Introduction -- Materials and methods -- Results -- Discussion -- Conclusions -- Literature cite

Bird Cryptochrome 1a Is Excited by Blue Light and Forms Long-Lived Radical- Pairs

Cryptochromes (Cry) have been suggested to form the basis of light-dependent magnetic compass orientation in birds. However, to function as magnetic compass sensors, the cryptochromes of migratory birds must possess a number of key biophysical characteristics. Most importantly, absorption of blue light must produce radical pairs with lifetimes longer than about a microsecond. Cryptochrome 1a (gwCry1a) and the photolyase-homology-region of Cry1 (gwCry1-PHR) from the migratory garden warbler were recombinantly expressed and purified from a baculovirus/Sf9 cell expression system. Transient absorption measurements show that these flavoproteins are indeed excited by light in the blue spectral range leading to the formation of radicals with millisecond lifetimes. These biophysical characteristics suggest that gwCry1a is ideally suited as a primary light-mediated, radical-pair-based magnetic compass recepto

Exceptional and Able: Supporting the Social Communication Skills of Gifted Neurodiverse Students in the Classroom

These are the presentation slides from the 2022 MEGA Conference (Mobile, AL) sponsored by the Alabama State Department of Education