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Presents the short story "Accidents," an excerpt from "Oh, Sister," by Patrick O'Keeffe.

Describes the design of a compact electron cyclotron resonance (ECR) plasma source for plasma-assisted processing of future semiconductor devices. Plasma characterization; Components of the compact ECR plasma source.

Examines the backbond oxidation of porous silicon surfaces resulting from oxygen radical irradiation. Relationship between irradiation time, photoluminescence (PL) intensity and oxygen related absorption; Application of the Fourier-transform infrared spectroscopy; Implications of backbond oxidation for PL enhancement.

The poem "Last-Day Vendor" by Patrick Lawrence O'Keeffe is presented. First Line: Step on the pedal. Last Line: biting into a fresh peach.

Photoelectron spectroscopy, mass spectrometry and electron–ion coincidence experiments combined with tunable synchrotron radiation have been used to study the decay and fragmentation of 2Cl-pyrimidine after Cl(2p), C(1s) and N(1s) excitations. The goal is to investigate how the state- and site-selected excitation and the chemical environment affect the fragmentation paths of the molecule and to make a comparison with fragmentation induced by direct valence ionization. It has been found that the site-selective inner shell excitation affects the branching ratio of the fragments, while the particular fragmentation channels of the cation are determined by the final state populated in the resonant decay of the core excited states. Effects of nuclear motion in the core excited states and the possible ultrafast molecular dissociation following the Cl(2p → σ*) core excitation are discussed. [ABSTRACT FROM AUTHOR]

Time-resolved polarization-dependent transient absorption has been used to study the plasmonicity of the optical transitions of Ag nanoparticles and nanoclusters. The lack of a measureable polarization anisotropy in the nanoparticles is indicative of the ultrafast electron-electron scattering while the anisotropy with a depolarization timescale of 500 fs observed in the nanoclusters indicates the excitation of a non-plasmonic state. The short lifetime of the anisotropy is a measure of electronic coupling between nearly degenerate states and is thus proposed as a sensitive measurement of the plasmonic content of the optical transitions of nanoclusters. [ABSTRACT FROM AUTHOR]

Noble metal nanoparticles exhibit localized plasmon resonance modes that span the visible and near‐infrared spectral ranges and have many applications. Modifying the size, shape, and composition of the nanoparticles changes the number of modes and their properties. The characteristics of these modes are transiently affected when illuminating the nano‐objects with ultrashort laser pulses. Here, core–shell gold–silver nanocuboids are synthesized and their spectral signature in the stationary and ultrafast transient regimes are measured. Their dipolar transverse mode vanishes with increasing Ag‐shell thickness, while higher‐order modes grow in the near‐ultraviolet range where no plasmon resonance can be generated with single noble metal nanoparticles. These higher‐energy modes are associated with sharp spectral variations of the ultrafast transient light extinction by the bimetallic nanocuboids. By carrying out a theoretical investigation, the different contributions to this response are broken down and a physical interpretation of its spectral profile is provided. The transient optical signal is then shown to reveal resonance modes hidden in the stationary regime spectra. [ABSTRACT FROM AUTHOR]

Ultrafast pump-probe spectroscopies have proved to be an important tool for the investigation of charge carriers dynamics in perovskite materials providing crucial information on the dynamics of the excited carriers, and fundamental in the development of new devices with tailored photovoltaic properties. Fast transient absorbance spectroscopy on mixed-cation hybrid lead halide perovskite samples was used to investigate how the dimensions and the morphology of the perovskite crystals embedded in the capping (large crystals) and mesoporous (small crystals) layers affect the hot-carrier dynamics in the first hundreds of femtoseconds as a function of the excitation energy. The comparative study between samples with perovskite deposited on substrates with and without the mesoporous layer has shown how the small crystals preserve the temperature of the carriers for a longer period after the excitation than the large crystals. This study showed how the high sensitivity of the time-resolved spectroscopies in discriminating the transient response due to the different morphology of the crystals embedded in the layers of the same sample can be applied in the general characterization of materials to be used in solar cell devices and large area modules, providing further and valuable information for the optimization and enhancement of stability and efficiency in the power conversion of new perovskite-based devices. [ABSTRACT FROM AUTHOR]

Vanadium-doped TiO 2 nanoparticles (V-TiO 2 NPs) with a V/Ti ratio of 3.0 at. % were prepared by gas-phase condensation and subsequent oxidation at elevated temperature. Both photocatalytic activity for -NO 2 reduction and photoelectrochemical water splitting were induced by V-doping in the visible spectral range λ> 450 nm, where undoped TiO 2 NPs are completely inactive. The photocatalytic properties were correlated with the ultrafast dynamics of the photoexcited charge carriers studied by femtosecond transient absorption (TA) spectroscopy with three different excitation wavelengths, i.e. λ e  = 330, 400, and 530 nm. Only in V-doped NPs, the photoexcitation of electrons into the conduction band by sub-bandgap irradiation (λ e  = 530 nm) was detected by TA spectroscopy. This observation was associated with electronic transitions from an intra-gap level localized on V 4+ cations. The photoexcited electrons subsequently relaxed, with characteristic times of 200–500 ps depending on λ e , into Ti-related surface traps that possessed suitable energy to promote -NO 2 reduction. The photoexcited holes migrated to long-lived surface traps with sufficient overpotential for the oxidization of both 2-propanol and water. On the basis of TA spectroscopy and photocurrent measurements, the position of the dopant-induced intra-gap level was estimated as 2.2 eV below the conduction band minimum. [ABSTRACT FROM AUTHOR]

The inclusion of aluminium (Al) nanoparticles (NPs) in chemical vapor deposition (CVD) diamond structures was achieved by depositing Al thin films on commercial CVD single-crystal diamond plates, and then covering them by a CVD diamond thin film to encapsulate the metal NPs formed by the dewetting occurring during the CVD process. Morphology and composition are investigated, showing a peculiar structure formed by an Al/diamond composite with both Al NPs and Al 2 O 3 islands included and surrounded in the diamond matrix, respectively. A mosaic-patterned homoepitaxial growth occurs for the capping diamond layer. The experimentally measured reflectivity matches the simulation of a system where the thickness of the Al/diamond composite layer is 1.80 ± 0.05 μm and the composition is 95 ± 2 % diamond and 5 ± 2 % Al. Simulations of the plasmonic response of Al NPs embedded in the diamond layer suggest that the decrease in transmission of the sample in the blue region of the spectrum is unlikely to be due to plasmonic absorption by the NPs. It is concluded that the shape of the transmission spectrum follows a Rayleigh-like scattering induced by the nanoporous diamond film. Ultrafast transient absorption measurements allow us to identify a sharp feature at 700 nm which can be associated with a modification of an interband transition in Al due to heating after photon absorption at 380 nm. [Display omitted] • Al nanoparticles were embedded in diamond to study the plasmonic response. • Despite a large increase in visible absorption, no plasmonic behavior was found. • Rayleigh like scattering is considered to explain the induced optical properties. • The formed structure can be applied in diamond systems to exploit visible light. [ABSTRACT FROM AUTHOR]

Analysis of carbon and water budgets in cropping systems is important for understanding the impacts of different management practices and meteorological conditions, in the context of climate change, on agriculture. We have established a pair of long-term eddy covariance flux towers at the R. J. Cook Agronomy Farm (CAF) near Pullman, Washington, US. The tower sites have similar crop rotation, weather conditions, and management practices except tillage. One site has been under no-till management (CAF-NT) since 1998, while the other site has used conventional tillage practice (CAF-CT) over the same time period. Measurements conducted above a garbanzo bean crop ( Cicer arietinum ) between October 2012 and September 2013 showed the CAF-NT site was close to CO 2 neutral with an annual cumulative net ecosystem exchange of CO 2 (NEE) of −20 ± 38 g C m −2 . By contrast, the CAF-CT site was a CO 2 source with an annual NEE of 117 ± 39 g C m −2 during the same time period. The annual NEE values at each site were significantly different ( p < 0.05). When carbon losses via harvest export were taken into account, the net rates of carbon loss from each ecosystem to the atmosphere were 32 ± 50 and 178 ± 48 g C m −2 for CAF-NT and CAF-CT, respectively, indicating CAF-NT was close to carbon neutral and CAF-CT was a net carbon source during the measurement period. Partitioning of NEE into gross primary productivity (GPP) and total ecosystem respiration ( R eco ) shows that the annual cumulative GPP of each site did not differ much, but CAF-NT had lower annual cumulative R eco compared to CAF-CT during the period of October 2012–September 2013. Water budget analyses presented similar magnitudes of annual sums of evapotranspiration (ET), 425 and 416 mm for CAF-NT and CAF-CT, respectively. ET was partitioned into evaporation ( E ) and transpiration ( T ) for both sites, and CAF-CT had a larger fraction of annual E compared to CAF-NT during the measurement period. Relationships between carbon and water fluxes were investigated, and for the period of October 2012–September 2013, high correlations were found in GPP vs. T and NEE vs. ET at both sites. In summary, the site deploying no-till practices had lower total ecosystem respiration and evaporation throughout the measurement period, more net carbon uptake and a greater ratio of transpiration over evapotranspiration ( T /ET) during the growing season. [ABSTRACT FROM AUTHOR]

Agricultural soils have the potential to be an important carbon (C) sink with proper management. The main goal of this study was to characterize C dynamics and net C exchange over two full crop years at two sites in the inland Pacific Northwest (iPNW). The iPNW is a highly productive dryland wheat growing region. The two measurement sites represent the low- and high-end of the regional precipitation gradient (250 and 550 mm year −1 , respectively). The low rainfall site is in a winter wheat-fallow rotation, while the high rainfall site is under continuous cropping with a rotation that includes winter wheat and pulse crops. The net ecosystem exchange of CO 2 (NEE) was monitored using the eddy covariance method. The winter wheat cropping years were strong CO 2 sinks, with net uptake of 517 ± 26 and 524 ± 29 g C m −2 year −1 at the high- and low-rainfall sites, respectively. The fallow and pulse-crop years were close to neutral with respect to NEE, with a net uptake of 20 ± 38 g C m −2 year −1 for garbanzo beans at the high rainfall site, and a net loss of 3 ± 19 g C m −2 year −1 for the fallow season at the low rainfall site. Combining NEE with other carbon exchange terms, most importantly carbon import and export via seeding and harvest, gives the net ecosystem carbon balance (NECB). We found that even when harvest export was taken into account, both sites acted as net carbon sinks over the two year period: the NECB at the continuous cropping site was 202 ± 60 g C m −2 , and the crop-fallow site had a NECB of 444 ± 34 g C m −2 . These results present useful insights to field-scale C dynamics on finely resolved timescales. To understand the potential of soils as a long term C sink however, longer-term monitoring over multiple complete crop rotation cycles in combination with other field measurements or process-based models will be necessary. [ABSTRACT FROM AUTHOR]

In the present work, we studied the photoinduced ion chemistry of the halogenated pyrimidines, a class of prototype radiosensitizing molecules, in the energy region 9-15 eV. The work was stimulated by previous studies on inner shell site-selective fragmentation of the pyrimidine molecule, which have shown that the fragmentation is governed by the population/formation of specific ionic states with a hole in valence orbitals, which in turn correlate to accessible dissociation limits. The combined experimental and theoretical study of the appearance energies of the main fragments provides information on the geometric structure of the products and on the role played by the specific halogen atom and the site of halogenation in the dissociation process. This information can be used to gain new insights on the elementary mechanisms that could possibly explain the enhanced radiation damage to the DNA bases or to the medium in which the bases are embedded, thereby contributing to their radiosensitizing effect. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

• Reanalyzed 12 site-years' carbon budget to account for measurement bias. • Bias adjustment caused a reduced magnitude of the carbon sink for every site-year. • Degree of change in magnitude is dependent on lushness of vegetation and data gaps. • Carbon sink-strength may be overestimated due to the bias of the instrumentation. During the Regional Approaches to Climate Change (REACCH) program, eddy covariance monitoring over agricultural fields were used to estimate annual carbon and water budgets in the inland Pacific Northwest. Here, we assess the effect of a bias in the high-frequency CO 2 concentration measurements using the Campbell Scientific EC150 infra-red gas analyzer on the CO 2 fluxes and field-scale carbon balances. The bias stems from using a lower frequency temperature measurement to calculate the CO 2 density, which misses higher frequency temperature fluctuations. To generate the bias adjustment, data were collected over four similar agricultural sites as part of the Long-Term Agroecosystem Research network for multiple months using the same four instrument sets used in the REACCH project. The difference between the high-frequency and low-frequency CO 2 fluxes were regressed against the kinematic heat fluxes to generate a correction equation for each instrument set, which were applied to the historical REACCH data to determine the effect of the bias on the measured and gap-filled flux values. The re-calculated positive biases in the measured fluxes were 40 gC-CO 2 m−2 yr-1 to 126 gC-CO 2 m−2 yr-1, indicating greater losses to the atmosphere than initially estimated. Once gap-filled, three out of fourteen site-years switched from weak carbon sinks to weak carbon sources. When the carbon exported via harvest was included in the budget calculation the bias correction still impacted the source/sink strength but did not change the sign of the carbon balance. Overall, the total net ecosystem exchange decreased between 300–470 gC-CO 2 m-2 per site (29–46%) over the 4 crop-years from the bias adjustment process. [ABSTRACT FROM AUTHOR]

In this paper, we present a comprehensive study of the carrier dynamics and optical properties of ZnSe nanowires (NWs). The transparency of the sample, obtained by the growth of the ZnSe NWs on glass, allowed us to perform transmittance, reflectance, photoluminescence (PL), time-resolved PL, and pump-probe transient absorption spectroscopy on as-grown samples. All measurements were performed at room temperature. Strong light trapping at the band-gap energy has been observed in reflectivity measurements. Fast transient absorption bleaching due to band filling and band-gap renormalization has been observed. The band-gap renormalization has a rise time constant of about 170 fs and a decay time of about 4 ps. Fast transient absorption bleaching is also observed at energies below the band gap, suggesting that intrinsic processes prevail over extrinsic photoinduced transitions in our high-quality NWs. The PL reveals the presence at room temperature of excitonic emission that shows a decay time of 0.5 ns. All of these features indicate that our ZnSe NWs have quality comparable to epitaxial films and can be used for optical devices and nonlinear optics. [ABSTRACT FROM AUTHOR]

This article draws on the concept of cultural humility, to describe and analyze a decolonizing approach to co-designing a primary prevention basketball program for young African-Australian people in Melbourne, Australia. We explore the potential for genuine collaboration and power-sharing with a culturally diverse community through collaboratively developing the co-design process and resultant program design. This article highlights the central role of UBUNTU in the co-design process, prioritizing African ways of knowing, being, and doing within a Westernized social work and design context. Through reporting on the stages of program design, we offer an example of how Indigenous knowledges and philosophies such as UBUNTU might be incorporated into co-design through cultural humility. We suggest this allows for a transformation of design tools and processes in ways that undermine oppressive and marginalizing power imbalances in design and social work., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The electron injection efficiency and the steady state absorptance at different photon energies for a composite system made of Au NPs embedded in a cerium oxide matrix are reported. Cerium oxide can be coupled with plasmonic nanoparticles (NPs) to improve its catalytic properties by visible-light absorption. The present work is a study of the ultrafast dynamics of excited states induced by ultraviolet and visible-light excitation in Au NPs combined with cerium oxide, aimed at understanding the excitation pathways. The data, obtained by femtosecond transient absorption spectroscopy, show that the excitation of localized surface plasmon resonances (LSPRs) in the Au NPs leads to an ultrafast injection of electrons into the empty 4f states of the surrounding cerium oxide. Within the first few picoseconds, the injected electrons couple with the lattice distortion forming a polaronic excited state, with similar properties to that formed after direct band gap excitation of the oxide. At sub-picosecond delay times, we observed relevant differences in the energetics and the time dynamics as compared to the case of band gap excitation of the oxide. Using different pump energies across the LSPR-related absorption band, the efficiency of the electron injection from the NPs into the oxide was found to be rather high, with a maximum above 30%. The injection efficiency has a different trend in energy as compared to the LSPR-related static optical absorptance, showing a significant decrease in low energies. This behavior is explained considering different deexcitation pathways with variable weight across the LSPR band. The results are important for the design of materials with high overall solar catalytic efficiency., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Zn-salophen complexes are a promising class of fluorescent chemosensors for nucleotides and nucleic acids. We have investigated, by means of steady state UV-Vis, ultrafast transient absorption, fluorescence emission and time dependent density functional theory (TD-DFT) the behavior of the excited states of a salicylidene tetradentate Schiff base (Sal), its Zn(II) coordination compound (Zn-Sal) and the effect of the interaction between Zn-Sal and adenosine diphosphate (ADP). TD-DFT shows that the deactivation of the excited state of Sal occurs through torsional motion, due to its rotatable bonds and twistable angles. Complexation with Zn(II) causes rigidity so that the geometry changes in the excited states with respect to the ground state structure are minimal. By addition of ADP to a freshly prepared Zn-Sal ethanol solution, a longer relaxation constant, in comparison to Zn-Sal, was measured, indicative of the interaction between Zn-Sal and ADP. After a few days, the Zn-Sal-ADP solution displayed the same static and dynamic behavior of a solution containing only the Sal ligand, demonstrating that the coordination of the ADP anion to Zn(II)leads to the demetallation of the Sal ligand. Fluorescence measurements also revealed an enhanced fluorescence at 375 nm following the addition of ADP to the solution, caused by the presence of 2,3-diamino naphthalene that is formed by demetallation and partial decomposition of the Sal ligand. The efficient fluorescence of this species at 375 nm could be selectively detected and used as a probe for the detection of ADP in solution., (© 2022. The Author(s).)

The COVID-19 pandemic is both a health and an economic crisis. Economically, lockdowns across Australia have devastated business and industry, creating immediate spikes in under- and unemployment. These impacts intersect with the precarious labour market of casualised and "gig" economy work, where young workers constitute an established and substantial group. While negatively impacting upon many young people's lives, in recent decades precarious employment has also been normalised for young people as they are encouraged to understand themselves as self-reliant and entrepreneurial in their working lives. Yet, these workers have been largely abandoned in the government's economic response to COVID-19. The economic impact and government response to the pandemic substantially disadvantage young people. This article analyses the impact of new government initiatives: the "JobKeeper" wage subsidy scheme, "JobSeeker" payments and early access to superannuation, "JobMaker" economic recovery plan and the redesign of university fees. These initiatives compound preexisting youth policy of low welfare levels, youth wages and high university fees to economically burden young people. Contrasting the repeated expression of anything pandemic related as "unprecedented", we argue that the economic abandonment of young people in the immediate COVID-19 crisis continues a decades-long precedent in Australia of economically disadvantaging young people., Competing Interests: The authors report no conflict of interest., (© 2021 Australian Social Policy Association.)

Expanding the activity of wide bandgap semiconductors from the UV into the visible range has become a central goal for their application in green solar photocatalysis. The hybrid plasmonic/semiconductor system, based on silver nanoparticles (Ag NPs) embedded in a film of CeO 2 , is an example of a functional material developed with this aim. In this work, we take advantage of the chemical sensitivity of free electron laser (FEL) time-resolved soft X-ray absorption spectroscopy (TRXAS) to investigate the electron transfer process from the Ag NPs to the CeO 2 film generated by the NPs plasmonic resonance photoexcitation. Ultrafast changes (<200 fs) of the Ce N 4,5 absorption edge allowed us to conclude that the excited Ag NPs transfer electrons to the Ce atoms of the CeO 2 film through a highly efficient electron-based mechanism. These results demonstrate the potential of FEL-based TRXAS measurements for the characterization of energy transfer in novel hybrid plasmonic/semiconductor materials.

The ultrafast dynamics of excited states in cerium oxide are investigated to access the early moments of polaron formation, which can influence the photocatalytic functionality of the material. UV transient absorbance spectra of photoexcited CeO 2 exhibit a bleaching of the band edge absorbance induced by the pump and a photoinduced absorbance feature assigned to Ce 4f → Ce 5d transitions. A blue shift of the spectral response of the photoinduced absorbance signal in the first picosecond after the pump excitation is attributed to the dynamical formation of small polarons with a characteristic time of 330 fs. A further important result of our work is that the combined use of steady-state and ultrafast transient absorption allows us to propose a revised value for the optical gap for ceria ( E og = 4 eV), significantly larger than usually reported.

Upon photoexcitation with a femtosecond laser pulse, the plasmonic resonance of a nanorod can couple with coherent vibrational modes generating a regular oscillating pattern in the transient absorbance of the nanostructure. The dynamics of the plasmon resonances of these materials are probed through femtosecond transient absorption spectroscopy in the spectral region between 400 nm and 1600 nm. Whereas in the visible range the spectra are comparable with the findings reported in the literature, the analysis of the transient NIR spectra revealed that their oscillation frequencies vary with wavelength, resulting in a strong distortion of the transient features that can be related to the specific lengths distribution of the nanorods contained in the sample. These findings suggest that in the design of efficient and highly sensitive gold-nanorod based plasmonic sensors a narrow size distribution of nanostructures is required.

In this work we show how the optical properties of ZnSe nanowires are modified by the presence of Ag nanoparticles on the sidewalls of the ZnSe nanowires. In particular, we show that the low-temperature luminescence of the ZnSe nanowires changes its shape, enhancing the phonon replicas of impurity-related recombination and affecting rise and decay times of the transient absorption bleaching at room temperatures, with an increase of the former and a decrease of the latter. In contrast, the deposition of Au nanoparticles on ZnSe nanowires does not change the optical properties of the sample. We suggest that the mechanism underlying these experimental observations is energy transfer via a resonant interaction, based on the fact that the localized surface plasmon resonance (LSPR) of Ag nanoparticles spectrally overlaps with absorption and emission of ZnSe, while the Au LSPR does not.