bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigations of powder flow patterns in hopper model through discrete element method
Authors: Kumar Vineet , Arora Rahul , Goyal Deepam , Pal Dinesh , Sehgal Shankar
Published: May 2019

In this paper, a comparative study was conducted to observe the flow patterns of bulk powder materials through a conical shaped hopper. Hoppers were designed based on Jenike charts and further analyzed using discrete element method. The paper focuses on the flow of micro-sized powder materials and how their area flow pattern changes along with velocity distribution variation with a change in hopper angle. Discrete element method was used to predict the flow patterns for different hopper angles and to study the transition of flow from funnel flow to mass flow. A comparison was made among these hoppers based on their average velocity and average mass flow rate to have an optimum design for mass flow. It was observed that a decrease in hopper angle resulted in an increase in both the mass flow rate and average velocity.
Goal statements in brain injury rehabilitation: A cohort study of client-centredness and relationship with goal outcome
Authors: Prescott Sarah , Doig Emmah , Fleming Jennifer , Weir Nicole
Published: May 2019

Background:

Currently, there is increasing recognition of the need to use a client-centred approach to goal setting in rehabilitation. However, there is limited research to guide practice with community-dwelling clients with acquired brain injury. An understanding of the characteristics of client-centred goals and the extent to which client-centeredness influences goal outcomes is required.

Objective:

To examine the relationships between the client-centredness of goals and their characteristics, content, recall and outcomes of client-centred goals in brain injury rehabilitation.

Methods:

A prospective cohort design study was employed. Participants were 45 clients with brain injury receiving outpatient rehabilitation, who completed measures of client-centredness after goal setting. Each goal was classified according to whether it was specific, measurable, non-jargonistic, and participation-focussed, included a timeframe and was recalled by participants.

Results:

Participants set 223 goals with 20 clinicians from multiple disciplines. Levels of client-centredness did not differ according to the characteristics, content and recall of goals, with the exception of goal specificity (p< 0.01). Client-centredness was significantly and positively correlated with goal outcomes (p< 0.05).

Conclusions:

The use of client-centred goals is recommended for improved rehabilitation outcomes. Applying goal documentation criteria does not necessarily mean that goals will be client-centred, and highly specific goal statements may not reflect what is important and meaningful to clients.
Impact of an antimicrobial stewardship intervention in India: Evaluation of post-prescription review and feedback as a method of promoting optimal antimicrobial use in the intensive care units of a tertiary-care hospital
Authors: Rupali Priscilla , Palanikumar Prasannakumar , Shanthamurthy Divyashree , Peter John Victor , Kandasamy Subramani , Zacchaeus Naveena Gracelin Princy , Alexander Hanna , Thangavelu Premkumar , Karthik Rajiv , Abraham Ooriapadickal Cherian , Michael Joy Sarojini , Paul Hema , Veeraraghavan Balaji , Chacko Binila , Jeyaseelan Visalakshi , Alangaden George , Prentiss Tyler , Zervos Marcus J
Published: May 2019

Objective:

Antimicrobial stewardship programs (ASPs) are effective in developed countries. In this study, we assessed the effectiveness of an infectious disease (ID) physician–driven post-prescription review and feedback as an ASP strategy in India, a low middle-income country (LMIC).

Design and setting:

This prospective cohort study was carried out for 18 months in 2 intensive care units of a tertiary-care hospital, consisting of 3 phases: baseline, intervention, and follow up. Each phase spanned 6 months.

Participants:

Patients aged ≥15 years receiving 48 hours of study antibiotics were recruited for the study.

Methods:

During the intervention phase, an ID physician reviewed the included cases and gave alternate recommendations if the antibiotic use was inappropriate. Acceptance of the recommendations was measured after 48 hours. The primary outcome of the study was days of therapy (DOT) per 1,000 study patient days (PD).

Results:

Overall, 401 patients were recruited in the baseline phase, 381 patients were recruited in the intervention phase, and 379 patients were recruited in the follow-up phase. Antimicrobial use decreased from 831.5 during the baseline phase to 717 DOT per 1,000 PD in the intervention phase (P < .0001). The effect was sustained in the follow-up phase (713.6 DOT per 1,000 PD). De-escalation according to culture susceptibility improved significantly in the intervention phase versus the baseline phase (42.7% vs 23.6%; P < .0001). Overall, 73.3% of antibiotic prescriptions were inappropriate. Recommendations by the ID team were accepted in 60.7% of the cases.

Conclusion:

The ID physician–driven implementation of an ASP was successful in reducing antibiotic utilization in an acute-care setting in India.
Quasistatic magnetoconvection: heat transport enhancement and boundary layer crossing
Authors: Lim Zi Li , Chong Kai Leong , Ding Guang-Yu , Xia Ke-Qing
Published: May 2019

We present a numerical study of quasistatic magnetoconvection in a cubic Rayleigh–Bénard (RB) convection cell subjected to a vertical external magnetic field. For moderate values of the Hartmann number $Ha$ (characterising the strength of the stabilising Lorentz force), we find an enhancement of heat transport (as characterised by the Nusselt number $Nu$). Furthermore, a maximum heat transport enhancement is observed at certain optimal $Ha_{opt}$. The enhanced heat transport may be understood as a result of the increased coherence of the thermal plumes, which are elementary heat carriers of the system. To our knowledge this is the first time that a heat transfer enhancement by the stabilising Lorentz force in quasistatic magnetoconvection has been observed. We further found that the optimal enhancement may be understood in terms of the crossing of the thermal and the momentum boundary layers (BL) and the fact that temperature fluctuations are maximum near the position where the BLs cross. These findings demonstrate that the heat transport enhancement phenomenon in the quasistatic magnetoconvection system belongs to the same universality class of stabilising–destabilising (S–D) turbulent flows as the systems of confined Rayleigh–Bénard (CRB), rotating Rayleigh–Bénard (RRB) and double-diffusive convection (DDC). This is further supported by the findings that the heat transport, boundary layer ratio and temperature fluctuations in magnetoconvection at the boundary layer crossing point are similar to the other three cases. A second type of boundary layer crossing is also observed in this work. In the limit of $Re\gg Ha$, the (traditionally defined) viscous boundary $\unicode[STIX]{x1D6FF}_{v}$ is found to follow a Prandtl–Blasius-type scaling with the Reynolds number $Re$ and is independent of $Ha$. In the other limit of $Re\ll Ha$, $\unicode[STIX]{x1D6FF}_{v}$ exhibits an approximate ${\sim}Ha^{-1}$ dependence, which has been predicted for a Hartmann boundary layer. Assuming the inertial term in the momentum equation is balanced by both the viscous and Lorentz terms, we derived an expression $\unicode[STIX]{x1D6FF}_{v}=H/\sqrt{c_{1}Re^{0.72}+c_{2}Ha^{2}}$ (where $H$ is the height of the cell) for all values of $Re$ and $Ha$, which fits the obtained viscous boundary layer well.
Trailing-edge flow manipulation using streamwise finlets
Authors: Afshari Abbas , Azarpeyvand Mahdi , Dehghan Ali A. , Szőke Máté , Maryami Reza
Published: May 2019

The use of streamwise finlets as a passive flow and aerodynamic noise-control technique is considered in this paper. A comprehensive experimental investigation is undertaken using a long flat plate, and results are presented for the boundary layer and surface pressure measurements for a variety of surface treatments. The pressure–velocity coherence results are also presented to gain a better understanding of the effects of the finlets on the boundary layer structures. The results show that the flow behaviour downstream of the finlets is strongly dependent on the finlet spacing. The use of finlets with coarse spacing leads to a reduction in pressure spectrum at mid- to high frequencies and an increase in spanwise length scale in the trailing-edge region due to flow channelling effects. For the finely distributed finlets, the flow is observed to behave similarly to that of a permeable backward-facing step, with significant suppression of the high-frequency pressure fluctuations but an elevation at low frequencies. Furthermore, the convection velocity is observed to reduce downstream of all finlet treatments. The trailing-edge surface pressure spectrum results have shown that, in order to obtain maximum unsteady pressure reduction, the finlet spacing should be of the order of the thickness of the inner layer of the boundary layer. A thorough study is provided for understanding of the underlying physics of both categories of finlets and their implications for controlling the flow and noise generation mechanism near the trailing edge.
Adjoint-based shape optimization of the microchannels in an inkjet printhead
Authors: Kungurtsev Petr V. , Juniper Matthew P.
Published: May 2019

In drop-on-demand inkjet printheads, ink is pumped steadily through small channels, each of which contains an actuator and a nozzle. When an actuator pulses, a droplet is forced through the nozzle, after which acoustic oscillations reverberate within the channel. Manufacturers would like to damp the residual reverberations, without increasing the pressure drop required to drive the steady flow. In this paper we use gradient-based optimization to show that this can be achieved by constricting the channel where the acoustic velocity is largest and enlarging the channel where the acoustic velocity is smallest. This increases the viscothermal dissipation of the acoustics without changing the viscous dissipation of the steady flow. We separate the compressible Navier–Stokes equations into equations for a steady flow with no oscillations and equations for oscillations with no steady flow. We define two objective functions: the viscous dissipation of the steady flow and the dissipation of the oscillations. We then derive the adjoints for both sets of equations, and obtain expressions for the gradient of each objective function with respect to boundary deformations in Hadamard form. We combine these with a gradient-based optimization algorithm, incorporating constraints such as the shapes of the actuator and nozzle. This algorithm quickly converges to a design that has the same viscous dissipation for the steady flow but a 50 % larger decay rate for the oscillating flow. We show that this design is nearly optimal. It is a shape that inkjet manufacturers, using physical insight and trial and error, have probably not yet considered. We also show how the adjoint fields provide physical insight into the mechanisms affecting each objective function. The main requirements of this method are that the steady flow Mach number and oscillating flow Mach number are small, and that dissipation is dominated by thermoviscous mechanisms. These requirements are often satisfied in microfluidics, so the method in this paper could be applied to many other applications.
A tale of two approaches to heteroclinic solutions for Φ-Laplacian systems
Authors: Ruan Yuan L.
Published: May 2019

In this article, the existence of heteroclinic solution of a class of generalized Hamiltonian system with potential $V : {\open R}^{n} \longmapsto {\open R}$ having a finite or infinite number of global minima is studied. Examples include systems involving the p-Laplacian operator, the curvature operator and the relativistic operator. Generalized conservation of energy is established, which leads to the property of equipartition of energy enjoyed by heteroclinic solutions. The existence problem of heteroclinic solution is studied using both variational method and the metric method. The variational approach is classical, while the metric method represents a more geometrical point of view where the existence problem of heteroclinic solution is reduced to that of geodesic in a proper length metric space. Regularities of the heteroclinic solutions are discussed. The results here not only provide alternative solution methods for Φ-Laplacian systems, but also improve existing results for the classical Hamiltonian system. In particular, the conditions imposed upon the potential are very mild and new proof for the compactness is given. Finally in ℝ2, heteroclinic solutions are explicitly written down in closed form by using complex function theory.
How social networking site addiction drives university students’ academic achievement: The mediating role of learning engagement
Authors: Li Yuan , Yao Chong , Zeng Siyao , Wang Xinye , Lu Tianjiao , Li Chenlin , Lan Jijun , You Xuqun
Published: May 2019

The main aim of this study was to explore the mediating role of learning engagement on the relationship between social networking site (SNS) addiction and academic achievement among 406 university students. The Social Networking Site Addiction Scale, Utrecht Work Engagement Scale for Students, and Chinese Students Academic Achievement Scale were used to evaluate students’ SNS addiction, learning engagement, and academic achievement. Correlation analysis indicated that SNS addiction, learning engagement, and academic achievement were significantly correlated with each other. The causal steps regression and bootstrap analysis show that learning engagement mediated the relationship between SNS addiction and academic achievement. Implications for research and instructions for how to improve university students’ academic achievement are discussed.
Challenging the frivolities of power: the ubiquitous camera and Nigerian political elites
Authors: Agbo George Emeka
Published: May 2019

The last decade has witnessed the ubiquitous presence of camera devices, from conventional cameras to communication gadgets (such as mobile phones, iPads and tablets), built with the capacity to produce, edit, disseminate and interact through photographs. In this article, I analyse visual materials circulated on Facebook, YouTube and Nairaland (a locally popular social-networking website used by Nigerians) to demonstrate how the ubiquity of the camera, its overt and surreptitious use, and the transformation and circulation of the resulting photographs constitute political acts in a postcolonial African context. The camera's ubiquity encompasses the increasing availability of photographic devices, but also the growing, and politically charged, inclination to put them to use, framing the world through which their users move. The production and dissemination of the resulting photograph gives it the status of an eyewitness account, amidst contestations that heighten its force as political articulation. Lastly, the ubiquitous camera is a means through which the public observes, polices and exposes the duplicity of state functionaries. The article contributes to an understanding of the ways in which digital infrastructure allows public access to the political undertaking of photography.
A NOTE ON THE SUM OF RECIPROCALS
Authors: DING YUCHEN , SUN YU-CHEN
Published: May 2019

We prove that, given a positive integer $m$, there is a sequence $\{n_{i}\}_{i=1}^{k}$ of positive integers such that $$\begin{eqnarray}m=\frac{1}{n_{1}}+\frac{1}{n_{2}}+\cdots +\frac{1}{n_{k}}\end{eqnarray}$$ with the property that partial sums of the series $\{1/n_{i}\}_{i=1}^{k}$ do not represent other integers.
THE NUMBER OF CYCLIC SUBGROUPS OF FINITE ABELIAN GROUPS AND MENON’S IDENTITY
Authors: TĂRNĂUCEANU MARIUS
Published: May 2019

We give a new formula for the number of cyclic subgroups of a finite abelian group. This is based on Burnside’s lemma applied to the action of the power automorphism group. The resulting formula generalises Menon’s identity.
DuPont and the Limits of Corporate Environmentalism
Authors: Rome Adam
Published: May 2019

In 1989, Edgar Woolard began his tenure as chief executive of the chemical giant DuPont by calling for a new “corporate environmentalism.” DuPont has changed dramatically since then to become more environmentally sustainable, but the company still has a poor record in some areas. The sustainability push also had mixed financial consequences. Though eco-efficiencies saved DuPont billions of dollars, the effort to create more sustainable engines of corporate growth failed to meet Wall Street expectations. The DuPont story offers important insights into the difficulties of greening an established industrial enterprise.
Renewing Business History in the Era of the Anthropocene
Authors: Bergquist Ann-Kristin
Published: May 2019

This special issue is concerned with new approaches in business history to exploration of the role of business in both creating and addressing the mounting environmental crisis that has become apparent over the last half century. Two decades have passed sinceBusiness History Reviewpublished a pioneering special issue on business and the natural environment. The guest editors of that issue, Christine Rosen and Christopher Sellers, called for an “ecocultural approach” to business history and noted that strikingly little attention had been given to the issue of business and the natural environment in the field.
Introduction: The African Charter on Democracy, Elections and Governance at 10
Authors: Wiebusch Micha , Aniekwe Chika Charles , Oette Lutz , Vandeginste Stef
Published: May 2019

On various continents, intergovernmental organizations resort to legal engineering in order to promote democratic governance in their member states. Those legal efforts operate in a fluctuating political and societal environment, which they seek to transform but which, in turn, shapes the authority, the effectiveness and even the very nature of the legal instruments. As this Special Issue shows, this process of mutual influencing between law and context as interdependent variables also applies to the African Union's (AU) landmark instrument for democratic governance promotion. Roughly one decade after the adoption of the African Charter on Democracy, Elections and Governance (ACDEG), fascinating developments, challenges and questions have emerged, some of which were arguably not anticipated by its drafters. For example, who envisaged that the ACDEG might become a justiciable instrument before the African Court on Human and Peoples’ Rights? In the wake of popular uprisings in response to gross undemocratic practices, what normative guidance does the ACDEG offer in response to such developments?
Paleobiology of the Mesoproterozoic Billyakh Group, Anabar Uplift, Northern Siberia
Authors: Sergeev V. N. , Knoll A. H. , Grotzinger J. P.
Published: May 2019

Silicified peritidal carbonates of the Mesoproterozoic Kotuikan and Yusmastakh Formations, Anabar Uplift, northeastern Siberia, contain exceptionally well-preserved microfossils. The assemblage is dominated by ellipsoidal akinetes of nostocalean cyanobacteria (Archaeoellipsoides) and problematic spheroidal unicells (Myxococcoides); both are allochthonous and presumably planktonic. The assemblage also includes distinctive mat-forming scytonematacean and entophysalidacean cyanobacteria, diverse short trichomes interpreted as cyanobacterial hormogonia or germinated akinetes, rare longer trichomes, and several types of colonial unicells. Although many taxa in the Kotuikan-Yusmastakh assemblage are long-ranging prokaryotes, the overall character of the assemblage is distinctly Mesoproterozoic, with its major features shared by broadly coeval floras from Canada, China, India, and elsewhere in Siberia.

Microfossils also occur in middle to inner shelf shales of the Ust’-Il'ya and lower Kotuikan Formations. Leiosphaerid acritarchs (up to several hundred microns in diameter) characterize this facies. As in other Mesoproterozoic acritarch assemblages, acanthomorphic and other complex forms that typify Neoproterozoic assemblages are absent.

The combination in Billyakh assemblages of exceptional preservation and low eukaryotic diversity supports the hypothesis that nucleated organisms diversified markedly near the Mesoproterozoic–Neoproterozoic boundary. The assemblages also demonstrate the antiquity of cyanobacteria capable of cell differentiation and suggest the importance of both changing peritidal substrates and evolving eukaryotes in determining stratigraphic patterns of Proterozoic prokaryotes. The permineralized assemblage contains 33 species belonging to 17 genera. Ten new species or new combinations are proposed:Archaeoellipsoides costatusn. sp.,A. elongatusn. comb.,A. dolichosn. comb.,A. minorn. nom.,A. crassusn. comb.,A. majorn. comb.,A. bactroformisn. sp.,Veteronostocale mediumn. sp.,Filiconstrictosus cephalonn. sp., andPartitiofilum yakschiniin. sp.
Status of West Indian racers in the Lesser Antilles
Authors: Sajdak Richard A. , Henderson Robert W.
Published: May 2019

The Lesser Antilles are home to four species of snakes of the genus Alsophis, otherwise known as racers. All four have undergone severe range reductions; at least two subspecies are extinct and another, A. antiguae, now occupies only 0.1 per cent of its historical range. The authors investigated the current distribution of the snakes by field surveys and interviews with the people of the islands.
The status and conservation of the Chacoan peccary in Paraguay
Authors: Taber Andrew B.
Published: May 2019

The Chacoan peccary Catagonus wagneri is endemic to the dry thorn forest of the Gran Chaco of Paraguay, Argentina and Bolivia. Since its discovery by scientists in the 1970s its population has declined due to overhunting, habitat destruction, and possibly disease. As of 1989 about 5000 individuals are estimated to survive in the Paraguayan Chaco. Small dispersed populations still exist in Argentina and Bolivia, but more information is needed on the status of this species in those two countries. In Paraguay, Chacoan peccaries have almost disappeared from the two national parks within their range and the only significant population exists in an area where there are no reserves. The survival of this species depends on enforcing regulations against hunting both within and outside the national parks, translocating animals to the parks, establishing a system of reserves on private land in critical areas, training of Paraguayan wildlife professionals, and environmental education.
Belize—a last stronghold for manatees in the Caribbean
Authors: O'Shea Thomas J. , ‘Lex’ Salisbury Charles A.
Published: May 2019

Belize is a small country but it offers a safe haven for the largest number of manatees in the Caribbean. The authors' survey in 1989 revealed that there has been no apparent decline since the last study in 1977. However, there is no evidence for population growth either and as the Belize economy develops threats from fisheries, human pressure and declining habitat quality will increase. Recommendations are made to ensure that Belize safeguards its manatee populations.
Rockhopper penguins and other marine life threatened by driftnet fisheries at Tristan da Cunha
Authors: Ryan Peter G. , Cooper John
Published: May 2019

The oriental driftnet fleet, which is responsible for the large-scale mortality of non-target species in the Pacific Ocean, has extended its range to include the South Atlantic Ocean. Relatively little is known about the areas of operation and impacts of driftnetting in the South Atlantic as yet, but it is emerging that driftnetting is equally devastating to the fauna of this ocean. This paper reviews the impact of the driftnet fishery on non-target species in the central South Atlantic Ocean. Several lines of evidence suggest that fishing effort is focused on Tristan da Cunha, apparently resulting in considerable mortality of rockhopper penguins Eudyptes chrysocome and other marine organisms. Britain should take steps to curb this destructive fishing technique in Tristan waters.
The golden-backed uacari on the upper Rio Negro, Brazil
Authors: Barnett Adrian , da Cunha Aléxia Celeste
Published: May 2019

The golden-backed uacari Cacajao melanocephalus ouakary is one of South America's least-known monkeys. Listed as Vulnerable by the IUCN, it lives in remote areas of north-western Amazonia, as yet relatively unaffected by ecologically disruptive economic and technological activities. It inhabits swamp forests on black-water rivers during the main fruiting season and may move to dry land forests at other times of the year. The authors' survey showed that the animal was still common in the vicinity of subsistence communities, but is subject to heavy hunting pressure. Although the political situation in the area and the region's remoteness make it difficult to implement conservation plans, the authors propose a possible basis for a conservation plan for the golden-backed uacari and its habitat.
Reduction in the occurrence of distressing involuntary memories following propranolol or hydrocortisone in healthy women
Authors: Kamboj Sunjeev K. , Gong An Tong , Sim ZhiHui , Rashid Adrihani A. , Baba Ami , Iskandar Georges , Das Ravi K. , Curran H. Valerie
Published: May 2019

Background

Pharmacological treatments targeting the neuroendocrine stress response may hold special promise in secondary prevention of posttraumatic stress disorder (PTSD). However, findings from clinical trials have been inconsistent and the efficacy of specific drugs, their temporal window of efficacy, effective doses and the characteristics of likely treatment responders remain unclear.

Method

Using an experimental human model of distressing involuntary memory formation, we compare the effects of two drugs that have theoretical or empirical support as secondary preventive agents in PTSD. Eighty-eight healthy women (average age: 23.5 years) received oral propranolol (80 mg), hydrocortisone (30 mg), or matched placebo immediately after viewing a ‘trauma film’. They then completed daily, time-stamped intrusion diaries for 1 week, at the end of which, voluntary memory was tested.

Results

While neither drug affected voluntary memory for the trauma narrative, propranolol treatment was associated with 42% fewer, and hydrocortisone with 55% fewer intrusions across the week, relative to placebo. Additionally, propranolol reduced general trauma-like symptoms, and post-drug cortisol levels were negatively correlated with intrusion frequency in the hydrocortisone group.

Conclusions

Overall, this study shows substantial reductions in intrusive memories and preserved voluntary narrative-declarative memory following either propranolol or hydrocortisone in an experimental model of psychological trauma. As such, despite some inconsistencies in clinical trials, our findings support continued investigation of propranolol and hydrocortisone as secondary preventive agents for re-experiencing symptoms of PTSD. The findings also suggest that it is critical for future research to identify the conditions governing the preventive efficacy of these drugs in PTSD.
Controlling the movement of molecules
Authors: Langer Robert
Published: May 2019

The ability to control the movement of molecules is both fascinating scientifically as well as being critically important to the well-being of our planet and its people. In particular, the sustained release of molecules over prolonged periods at controlled rates has had and will continue to have enormous implications for the delivery of substances in medicine, agriculture, the environment, nutrition, aquaculture, household consumer products, and numerous other areas. This field is advancing at a rapidly accelerating pace. In this article, I largely discuss our own work, starting 45 years ago, in enabling the controlled release of macromolecules from biocompatible polymers. I also discuss the synthesis of novel materials to affect molecular movement and I then examine external approaches for controlling the movement of molecules through materials, using forces such as electric, acoustic, and magnetic fields. I further discuss approaches for controlling molecular movement through physiologic barriers, such as the skin, lung, and intestine. Finally, I outline several future areas of this field, including how it can affect the developing world, the ability to control the movement of molecules into mammalian cells, and the design of intelligent approaches to control molecular delivery.
Reciprocal Yield Analysis of Red Rice (Oryza sativa) Competition in Cultivated Rice
Authors: Pantone Dan J. , Baker John B.
Published: May 2019

Four years of field experiments were used to assess the competitive ability of red rice, a weedy variety of rice, and ‘Mars’, a cultivar of rice. Red rice was the dominant competitor each of the 4 yr, and an average of one red rice plant reduced Mars grain yield per plant equal to the effect of four Mars plants. Intervarietal competition was more important than intravarietal competition for Mars, whereas the reverse was true for red rice. The product of the coefficients for intravarietal competition did not significantly exceed the product of the coefficients for intervarietal competition, indicating that the two varieties were competing for the same resources. Using the reciprocal yield model coefficients from 1989, grain yield losses of Mars, due to red rice densities of 4, 16, 25, and 300 plants m−2, were predicted to approximate 13, 37, 48, and 92%, respectively, at a fixed cultivar density of 100 plants m−2.
Influence of Cultivation Timing on Chemical Control of Sicklepod (Cassia obtusifolia) in Soybean (Glycine max)
Authors: Shaw David R. , Newsom Larry J. , Smith Clyde A.
Published: May 2019

Cultivation timings were used in conjunction with postemergence herbicides to determine their effect on sicklepod control in soybean. Treatments using cultivation alone resulted in less than 70% sicklepod control. A postemergence application of chlorimuron following metribuzin applied postemergence was usually more effective in controlling sicklepod with cultivation 7 days after application than with cultivation 3 days before or at application, or with no cultivation. Cultivation at any timing in conjunction with a postemergence application of imazaquin following imazaquin preemergence improved sicklepod control compared to imazaquin without cultivation. Sicklepod control with chlorimuron postemergence followed by cultivation 7 days after application was as good as or better than two sequential applications of chlorimuron with no cultivation. Imazaquin or metribuzin preemergence followed only by cultivation provided less than 80% control in two of three experiments.
Wild Oat (Avena fatua) and Spring Barley (Hordeum vulgare) Interference in a Greenhouse Experiment
Authors: Morishita Don W. , Thill Donald C. , Hammel John E.
Published: May 2019

Intraspecific and interspecific interference effects on growth, gas exchange, and water potential of wild oat and spring barley were measured under greenhouse conditions using a 1:1.06 barley to wild oat replacement series. Intraspecific barley interference affected barley growth more than interspecific wild oat interference. Interspecific wild oat interference with barley reduced wild oat growth more than intraspecific interference. Wild oat plant height surpassed barley plant height near barley anthesis. Growth and gas exchange of barley and wild oat responded the same to short-term water stress.
Density and Spatial Interference of Barnyardgrass (Echinochloa crus-galli) with Rice (Oryza sativa)
Authors: Stauber Larry G. , Smith Roy J. , Talbert Ronald E.
Published: May 2019

Density and spatial interference of barnyardgrass with ‘Lemont’ and ‘Newbonnet’ rice cultivars was investigated in 1987 and 1988. Barnyardgrass reduced grain yield of Lemont, a semidwarf cultivar, more than Newbonnet, a short-statured cultivar. Linear regression indicated that season-long interference of barnyardgrass at 1 to 20 plants m–2reduced grain yields of Lemont and Newbonnet by 301 and 257 kg ha–1per barnyardgrass plant, respectively. Grain yields of Lemont and Newbonnet were reduced by barnyardgrass densities to 40 plants m–2but were not affected further at densities ≥40 plants m–2. Barnyardgrass reduced straw yield of Lemont more than of Newbonnet. Although barnyardgrass culms m–2and straw yield increased as weed density increased, the weed produced more culms per plant at 2 and 5 m–2than at 20 to 80 m–2. In a spatial interference experiment, Lemont grain yield reduction averaged 21% when plants were grown within 0 to 25 cm of a barnyardgrass plant group (group = 4 plants per 140 cm2). However, rice yields were not reduced when barnyardgrass plant groups were 25 to 50 or 50 to 100 cm away. Additional treatments included two barnyardgrass groups spaced 20, 40, 80, or 100 cm apart When Lemont grew between barnyardgrass groups spaced 20 or 40 cm apart, grain yields were reduced 40 and 27%, respectively, compared with weed-free rice. However, Lemont yield was not reduced when rice plants grew between weed plant groups spaced 100 cm apart.
Giant Ragweed (Ambrosia trifida) Interference in Soybeans (Glycine max)
Authors: Baysinger Jerry A. , Sims Barry D.
Published: May 2019

Field experiments were established near Portageville, MO, to determine the effects of giant ragweed interference in soybeans. Threshold densities of giant ragweed that reduced soybean yield were less than two plants 9 m−1of soybean row. This density reduced soybean seed yield 46 and 50% in 1988 and 1989, respectively, after full-season interference. The critical duration of giant ragweed interference in soybeans was between 4 and 6 weeks after emergence (WAE) in 1988 and between 2 and 4 WAE in 1989. Full-season giant ragweed interference at densities of 220 000 and 360 000 plants ha−1in 1988 and 1989, respectively, resulted in almost complete soybean yield loss. Eight to 10 weeks after emergence of giant ragweed-free conditions were required to prevent soybean yield reductions.
Interactions of Herbicides with Photosynthetic Electron Transport
Authors: Fuerst E. Patrick , Norman Michael A.
Published: May 2019

The two primary sites of herbicide action in photosynthetic electron transport are the inhibition of photosystem II (PS II) electron transport and diversion of electron flow through photosystem I (PS I). PS II electron transport inhibitors bind to the D1 protein of the PS II reaction center, thus blocking electron transfer to plastoquinone. Inhibition of PS II electron transport prevents the conversion of absorbed light energy into electrochemical energy and results in the production of triplet chlorophyll and singlet oxygen which induce the peroxidation of membrane lipids. PS I electron acceptors probably accept electrons from the iron-sulfur protein, Fa/Fb. The free radical form of the herbicide leads to the production of hydroxyl radicals which cause the peroxidation of lipids. Herbicide-induced lipid peroxidation destroys membrane integrity, leading to cellular disorganization and phototoxicity.
Toxicity of AC 263,222 to Purple (Cyperus rotundus) and Yellow Nutsedge (C.esculentus)
Authors: Richburg John S. , Wilcut John W. , Wehtje Glenn R.
Published: May 2019

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective placement of 5 cm of soil treated with AC 263,222 above and/or below nutsedge tubers. AC 263,222 applied early POST (EPOST) or POST at 71 g ai ha-1as a foliar, soil, or foliar + soil application also was evaluated. AC 263,222 applied below nutsedge tubers did not reduce purple or yellow nutsedge shoot number, shoot dry weight, shoot regrowth dry weight, or root-tuber dry weight. However, when it was applied above purple nutsedge tubers, shoot dry weight was reduced; and when it was applied above yellow nutsedge tubers, shoot dry weight and root dry weight were reduced. AC 263,222 applied 5 cm above + 5 cm below purple nutsedge tubers reduced shoot number, shoot dry weight, shoot regrowth dry weight, and root dry weight to 9, 4, 10, and 16% of the control, respectively, in purple nutsedge and to 23, 16, 9, and 15% of the control, respectively, in yellow nutsedge. AC 263,222 applied EPOST or POST reduced shoot dry weight, shoot regrowth dry weight, and root dry weight of purple nutsedge to less than or equal to 11, 7, and 27% of the control, respectively, and to less than or equal to 10, 16, and 29% of the control, respectively, for yellow nutsedge with no differences between application methods. The foliar and soil activity of AC 263,222 for purple and yellow nutsedge control provides an advantage over currently registered peanut herbicides.
Temperature and Water Status of Seed Affect Afterripening in Wild Oat (Avena fatua)
Authors: Foley Michael E.
Published: May 2019

Dormant wild oat seed require afterripening under warm-dry conditions for conversion to a nondormant state capable of germination. Research was conducted to determine the relationship between temperature and seed moisture levels on afterripening of dormant wild oat line M73 seed, and to evaluate the status of water binding in the dormant seed. Conversion of dormant wild oat seed to a nondormant state at 20 to 40 C occurs primarily in the range of 5 to 20% seed moisture. There is an inverse relationship between temperature and seed moisture content for afterripening as measured by seed germination. As the afterripening temperature increases, the seed moisture content must decrease for maximum afterripening (germination) to occur. Moisture isotherms and derived enthalpy curves indicate three regions of water binding which reflect decreased binding of water to seed components as the moisture content in the dormant seed increases. Maximum afterripening, in the second region of water binding, corresponds to seed moisture contents of 7 to 22%. In this region water is weakly associated with macromolecular surfaces and begins to have solvent properties. Because afterripening occurs mainly in the second region of water binding it is likely that individual enzymatic and nonenzymatic reactions, rather than metabolic processes, mediate the conversion of wild oat seed to the nondormant state.
Effect of Adjuvant on Foliar Absorption and Activity of Clethodim and Polar Degradation Products of Clethodim
Authors: Bridges David C. , Smith Albert E. , Falb Linford N.
Published: May 2019

Research was conducted to determine foliar absorption of14C-clethodim and its polar degradation products with five adjuvants and to compare the relative herbicidal activity of clethodim and its polar degradation products. Differential14C-clethodim and14C-polar degradation products absorption occurred among the five adjuvants. Adjuvants that mediated rapid foliar absorption of clethodim did not always mediate rapid foliar uptake of polar degradation products. Herbicidal activity of clethodim exceeded activity of polar degradation products regardless of time of day of application or whether adjuvant was used. Inclusion of adjuvant was required for herbicidal activity of polar degradation products. Clethodim activity declined when applied at 0800 h EDT compared to applications at 2000 h EDT. To maximize herbicidal activity of clethodim, adjuvants should be selected that mediate rapid foliar absorption of both clethodim and the polar degradation products of clethodim and that minimize photodegradation of clethodim.
Crop and Herbicide Rotations for Johnsongrass (Sorghum halepense) Control
Authors: Frans Robert E. , Mcclelland Marilyn R. , Horton Diana K. , Corbin Billy R. , Talbert Ronald E.
Published: May 2019

Four-year cropping sequences of continuous cotton, cotton-soybeans-soybeans-cotton, continuous soybeans, soybeans-grain sorghum-soybeans-grain sorghum, and cotton-rice-cotton-rice were treated each year with high and low levels of herbicides to control johnsongrass. High levels of herbicide were necessary to control johnsongrass in continuous cotton, cotton-soybeans-soybeans-cotton, continuous soybeans, and the soybeans-grain sorghum rotation. Johnsongrass was not eradicated, however, after 4 years of cropping sequences with high herbicide inputs. Both low and high levels of herbicide coupled with water management required for rice production controlled johnsongrass and prevented rice yield reductions.
Race Equality Policy Making in a Devolved Context: Assessing the Opportunities and Obstacles for a ‘Scottish Approach’
Authors: MEER NASAR
Published: May 2019

There is a burgeoning literature that suggests that, across a number of social policy domains, ‘Scotland is different’. Hitherto however, race equality policy has been largely overlooked and this article addresses this within the context of recent and historical developments in a devolved policy context. Adopting a mixed-method case-study analysis, including thirty-two semi-structured interviews with civil society and Scottish Government, the article shows how policy actors lack a consensus on the underlying causes of racial inequality, in ways that may impede policy making. In this sense, the article shows how Scotland ‘orbits’ around existing settlements, rather than necessarily setting off in a new course that goes beyond the fact of contingency. The implications of this analysis have a much broader relevance, including an account of how race equality policy opportunities encounter political obstacles, in a way that bears both specific and generalizable qualities. These include the role of policy coalitions in holding and promoting a coherent set of positions, the particularity of race as an idea or ‘cognitive problem’, and how prevailing narratives about national identities can feed into this process.
ALLE ORIGINI DELLA SCIENZA POLITICA ITALIANA: GAETANO MOSCA EPISTEMOLOGO
Authors: Fisichella Domenico
Published: May 2019

Introduzione

La riflessione epistemologica di Gaetano Mosca prende le mosse dall'osservazione che la scienza politica, come studio dei fenomeni politici con il metodo scientifico, è nel suo tempo ancora in fase di significativa arretratezza, per non dire nell'infanzia. Basta guardare allo sviluppo delle scienze naturali per rendersene conto. Già dalle pagine iniziali della Teorica dei governi e governo parlamentare, pubblicato in prima edizione nel 1884, il rilievo è esplicito e ricorrente: “i risultati ci dicono che, fino al giorno d'oggi, il metodo sperimentale ha fatto assai migliori prove nelle scienze fisiche che nelle sociali” (Mosca 1982, 197). D'altra parte, “che una scienza sociale non sia ancora nata”, talché ne deriva appunto “l'inferiorità di sviluppo scientifico che hanno le scienze sociali in rapporto alle naturali”, è tema ritornante anche negli Elementi di scienza politica, usciti in prima edizione nel 1896. “La scienza politica”, nota infatti il nostro autore, “non crediamo che neanche ora sia entrata interamente nel vero periodo scientifico” (ivi, 202, 199, 555).
SHEA-CDC TB Survey, Part I: Status of TB Infection Control Programs at Member Hospitals, 1989-1992
Authors: Fridkin Scott K. , Manangan Lilia , Bolyard Elizabeth ,   The Society for Healthcare Epidemiology of America, Jarvis William R.
Published: May 2019

Objective:

To determine trends in Mycobacterium tuberculosis infection in healthcare workers, tuberculosis (TB) control measures, and compliance with the 1990 Centers for Disease Control and Prevention (CDC) guideline for preventing transmission of TB in healthcare facilities.

Design:

Voluntary questionnaire sent to all members of the Society for Healthcare Epidemiology of America, representing 359 hospitals.

Results:

Respondents’ hospitals (210 [58%]) had a median of 2,400 healthcare workers (range, 396 to 13,745), 437 beds (range, 48 to 1,250), 5.6 patients with TB per year (range, 0 to 492), and 0 multidrug-resistant (MDR) TB patients per year (range, 0 to 33). Of 166 respondents’ hospitals for which data were provided for 1989 through 1992, the number caring for MDR-TB patients increased from 10 (6%) in 1989 to 49 (30%) in 1992. Reported policies for routine healthcare worker tuberculin skin testing varied. The median skin-test positivity rate for healthcare workers at the time of hire increased from 0.54% in 1989 to 0.81% in 1992, but the median conversion rate during routine testing remained similar: 0.35% in 1989 and 0.33% in 1992. Among 196 hospitals with reported data on respiratory protection use for 1989 through 1992, the use of either surgical submicron, dust-mist, or dust-fume-mist respirators for healthcare workers increased from 9 (5%) in 1989 to 85 (43%) in 1992. Of 181 hospitals with reported data, 113 (62%) had acid-fast bacilli isolation facilities consistent with the 1990 CDC guideline (ie, a single patient room, negative air pressure relative to the hallway, air exhausted directly outside, and ≥ 6 air exchanges per hour).

Conclusions:

While the number of surveyed hospitals caring for TB and MDR-TB patients increased during 1989 through 1992, TB infection control measures at many hospitals still did not meet the 1990 CDC guideline recommendations.
Evaluation of Infection Control Measures in Preventing the Nosocomial Transmission of Multidrug-Resistant Mycobacterium tuberculosis in a New York City Hospital
Authors: Stroud Leonardo A. , Tokars Jerome I. , Grieco Michael H. , Crawford Jack T. , Culver David H. , Edlin Brian R. , Sordillo Emilia M. , Woodley Charles L. , Gilligan Mary Ellen , Schneider Nancy , Williams Julie , Jarvis William R.
Published: May 2019

Objective:

To evaluate the efficacy of Centers for Disease Control and Prevention (CDC)-recommended infection control measures implemented in response to an outbreak of multidrug-resistant (MDR) tuberculosis (TB).

Design:

Retrospective cohort studies of acquired immunodeficiency syndrome (AIDS) patients and healthcare workers. The study period (January 1989 through September 1992) was divided into period I, before changes in infection control; period II, after aggressive use of administrative controls (eg, rapid placement of TB patients or suspected TB patients in single-patient rooms); and period III, while engineering changes were made (eg, improving ventilation in TB isolation rooms).

Setting:

A New York City hospital that was the site of one of the first reported outbreaks of MDR-TB among AIDS patients in the United States.

Participants:

All AIDS patients admitted during periods I and II. Healthcare workers on nine inpatient units with TB patients and six without TB patients.

Results:

The epidemic (38 patients) waned during period II and only one MDR-TB patient presented during period III. The MDR-TB attack rate among AIDS patients hospitalized on the same ward on the same days as an infectious MDR-TB patient was 8.8% (19 of 216) during period I, decreasing to 2.6% (5 of 193; P= 0.01) during period II. In a small group of healthcare workers with tuberculin skin test data, conversions during periods II through III were higher on wards with than without TB patients (5 of 29 versus 0 of 15; P= 0.15), although the difference was not statistically significant.

Conclusions:

Transmission of MDR-TB among AIDS patients decreased markedly after enforcement of readily implementable administrative measures, ending the outbreak. However, tuberculin skin-test conversions among healthcare workers may not have been prevented by these measures. CDC guidelines for prevention of nosocomial transmission of TB should be implemented fully at all US hospitals.
The Hospital Epidemiologist: Practical Ideas
Authors: Wenzel Richard P.
Published: May 2019

The modem hospital epidemiologist has broad perspectives and influence across clinical departmental lines. The opportunities to improve patient care by expanding traditional areas of focus beyond infection control are great. Useful skills include epidemiology, communication, and respect for colleagues.