bluuebunny/crossref_metadata_2025 huggingface dataset:
Second-order Markov chain models of rainfall in Ibadan, Southwest Nigeria
Authors: Ogunjo S. T. , Fuwape I. A. , Oluyamo S. S. , Rabiu A. B.
Published: February 2021

Understanding the dynamics of rainfall is important for maximizing the agricultural potential, environmental planning, as well as policy development. In this study, a two-state second-order Markov chain model was developed for the annual and daily occurrence of different rainfall sequences in Ibadan, southwestern Nigeria. The annual variation was adapted to a sine series model. The model was able to account for more than 30% of the observed variation. Markov chain approach to modelling rainfall in tropical region is unique because it considers the “memory” – previous rainfall events, which is lacking in other methods. The daily occurrences showed patterns consistent with tropical regions. Results from this study is significant for economic, health and environmental planning in the location.
Trends in extreme temperature indices over Lagos, Nigeria
Authors: Ogunjo S. T. , Akinsusi J. O. , Fuwape I. A.
Published: February 2021

There is the need to understand the trend and impact of extreme temperature on coastal cities because they are generally susceptible to extreme precipitation events. This study explores the trend in extreme temperature for Lagos State, Nigeria. The indices for daily minimum and maximum temperature data was calculated for the period 1991–2015 using the RClimDex software. The result showed that both minimum value of daily minimum temperature (TNn) and cool days (TX10p) showed negative trends among the indices considered. Significant trends were observed in warm nights (TN90p), warm days (TX90p) and mean of maximum temperature (Tmax-mean). Warm nights were found to be increasing while cold nights are either unchanged or decreasing. This study reveals that there are evidences of increase in warming of Lagos State.
Towards Improving Artisan and Craftsmen Productivity
Authors: Amusan L.M. , Oluwatobi O. , Dalshe C. , Ezenduka J. , Emetere M. , Owolabi J.D. , Tunji-Olayeni P.F.
Published: February 2021

The construction industry plays a noteworthy part in contribution to the gross domestic product of developing countries. Nigeria being a developing country, the construction industry is highly labour intensive labour intensive. For the purpose of this study, the data collection instrument used was structured questionnaire making use of the 5-point Likert scale. Sample size of 52 was chosen from population frame of 60 construction firms was adopted for the study. The study found out among other things that there should be periodic increase in wages of artisans and craftsmen, schedule should be mad flexible, provision of incentives and motivation, strategies such as periodic assessment of artisans skill should be implemented, stakeholders to have a say in artisan training and organizing training programs by construction firms. To this end the need for highly performing craftsmen construction industry is not debatable, Craftsmen are the major employee of the construction industry, since most of the work in the construction industry has to be done manually by hand, therefore they deserve to be well equipped and given the best of the training on account of their contributions.
Determination of volume of wastewater generated in a university campus
Authors: Omole D.O. , Chichezie T.E. , Akpan V.E.
Published: February 2021

The development of wastewater reuse schemes has been greatly slowed down by the lack of adequate wastewater generation data. Most data sources on wastewater generation provided by international organizations are mere estimates ofa nation’swastewater generation pattern and can only go a long way in explaining the wastewater situation of that nation. Intensive wastewater reuse schemes for futuristic purposes would require collection and storage of wastewater data for effective planning. This study identifies and closes that gap in a University campus where there is a high demand of water for daily use. Flowrates of wastewater being discharged into the environment was determined over a period of time using a standard weir and a level measuring tool. From this, the volume of wastewater generated was calculated. The results show that about 1,529,288 liters of wastewater was generated daily in the University campus. From this value, the water consumption rate of the university community was estimated to be 1,911,610 liters of water daily. From these findings, the wastewater generated within the Covenant University campus could be sufficient for agricultural, urban and other municipal reuse schemes. The environmental, economic and public health benefits from wastewater recycling are enormous and thus more attention must be given to its generation, treatment, disposal and reuse.
Enhancing catalytic epoxide ring-opening selectivity using surface-modified Ti3C2T
x
MXenes
Authors: Slot Thierry K , Natu Varun , Ramos-Fernandez Enrique V , Sepúlveda-Escribano Antonio , Barsoum Michel , Rothenberg Gadi , Shiju N Raveendran
Published: February 2021

MXenes are a new family of two-dimensional carbides and/or nitrides. Their 2D surfaces are typically terminated by O, OH and/or F atoms. Here we show that Ti3C2T
x
—the most studied compound of the MXene family—is a good acid catalyst, thanks to the surface acid functionalities. We demonstrate this by applying Ti3C2T
x
in the epoxide ring-opening reaction of styrene oxide (SO) and its isomerization in the liquid phase. Modifying the MXene surface changes the catalytic activity and selectivity. By oxidizing the surface, we succeeded in controlling the type and number of acid sites and thereby improving the yield of the mono-alkylated product to >80%. Characterisation studies show that a thin oxide layer, which forms directly on the Ti3C2T
x
surface, is essential for catalysing the SO ring-opening. We hypothesize that two kinds of acid sites are responsible for this catalysis: In the MXene, strong acid sites (both Lewis and Brønsted) catalyse both the ring-opening and the isomerization reactions, while in the Mxene–TiO2 composite weaker acid sites catalyse only the ring-opening reaction, increasing the selectivity to the mono-alkylated product.
Intersections and unions of a general family of function spaces
Authors: Bao Guanlong , Wulan Hasi , Ye Fangqin
Published: February 2021

In this paper, we investigate the strict inclusion relation associated with intersections and unions of a general family of function spaces. We answer partially a question left open in Korhonen and Rättyä [Comput. Methods Funct. Theory 5 (2005), pp. 459–469].
Bounds for an integral involving the modified Struve function of the first kind
Authors: Gaunt Robert
Published: February 2021

Simple upper and lower bounds are established for the integral

∫
0
x

e

−
β
t

t
ν

L

ν

(
t
)

d

t

\int _0^x\mathrm {e}^{-\beta t}t^\nu \mathbf {L}_\nu (t)\,\mathrm {d}t

, where

x
>
0

x>0

,

ν
>
−
1

\nu >-1

,

0
>
β
>
1

0>\beta >1

and

L

ν

(
x
)

\mathbf {L}_\nu (x)

is the modified Struve function of the first kind. These bounds complement and improve on existing results, through either sharper bounds or increased ranges of validity. In deriving our bounds, we obtain some monotonicity results and inequalities for products of the modified Struve function of the first kind and the modified Bessel function of the second kind

K

ν

(
x
)

K_{\nu }(x)

, as well as a new bound for the ratio

L

ν

(
x
)

/

L

ν
−
1

(
x
)

\mathbf {L}_{\nu }(x)/\mathbf {L}_{\nu -1}(x)

.
A note on decreasing rearrangement and mean oscillation on measure spaces
Authors: Burchard Almut , Dafni Galia , Gibara Ryan
Published: February 2021

We derive bounds on the mean oscillation of the decreasing rearrangement

f
∗

f^*

on

R

+

\mathbb {R}_+

in terms of the mean oscillation of

f
f

on a suitable measure space

X
X

. In the special case of a doubling metric measure space, the bound depends only on the doubling constant.
Multilinear multipliers and singular integrals with smooth kernels on Hardy spaces
Authors: Cruz-Uribe David , Nguyen Hanh
Published: February 2021

We consider weighted norm inequalities for multilinear multipliers whose symbols satisfy a product-type Hörmander condition. Our approach is to consider a more general family of multilinear singular integral operators associated to a family of smooth kernels that satisfy an

L
r

L^r

-Schwartz regularity condition. We give conditions for these operators to satisfy weighted Hardy space estimates and derive our results for multipliers as a special case. As an additional application, we use Rubio de Francia extrapolation to prove multilinear estimates on the variable exponent Hardy spaces.
Wild dynamics and asymptotically separated sets
Authors: Tapia-García Sebastián
Published: February 2021

Let

X
X

be a separable infinite dimensional (real or complex) Banach space. Hájek and Smith, in 2010, constructed a linear bounded operator

T
T

on

X
X

such that

A
T

≔
{
x
∈
X
:
 
‖

T
n

x
‖
→
∞
}

A_T≔\{x\in X:~ \|T^nx\|\to \infty \}

is not dense and has nonempty interior, whenever

X
X

admits a symmetric basis. Augé, in 2012, extended the previous construction to each separable Banach space, introducing the notion of wild operators. This work is divided in two parts. In the first part we define and explore the notion of asymptotically separated sets on Banach spaces, giving several examples whenever the ambient space has either finite or infinite dimension. We show how these sets can be used to construct operators with non-intuitive dynamics. Specifically, operators

T
:
X
→
X

T:X\rightarrow X

for which the set

A
T

A_T

and the set of recurrent points form a partition of the space. Secondly, we investigate geometric and spectral properties of operators with wild dynamic and we provide a wild operator whose spectrum is equal to the closed unit disk. We end this paper giving some comments about the norm closure of the set of wild operators.
Understanding crown shyness from a 3-D perspective
Authors: van der Zee Jens , Lau Alvaro , Shenkin Alexander
Published: February 2021

Background and Aims

Crown shyness describes the phenomenon whereby tree crowns avoid growing into each other, producing a puzzle-like pattern of complementary tree crowns in the canopy. Previous studies found that tree slenderness plays a role in the development of crown shyness. Attempts to quantify crown shyness have largely been confined to 2-D approaches. This study aimed to expand the current set of metrics for crown shyness by quantifying the characteristic of 3-D surface complementarity between trees displaying crown shyness, using LiDAR-derived tree point clouds. Subsequently, the relationship between crown surface complementarity and slenderness of trees was assessed.

Methods

Fourteen trees were scanned using a laser scanning device. Individual tree points clouds were extracted semi-automatically and manually corrected where needed. A metric that quantifies the surface complementarity (Sc) of a pair of protein molecules is applied to point clouds of pairs of adjacent trees. Then 3-D tree crown surfaces were generated from point clouds by computing their α shapes.

Key Results

Tree pairs that were visually determined to have overlapping crowns scored significantly lower Sc values than pairs that did not overlap (n = 14, P < 0.01). Furthermore, average slenderness of pairs of trees correlated positively with their Sc score (R2 = 0.484, P < 0.01), showing agreement with previous studies on crown shyness.

Conclusions

The characteristic of crown surface complementarity present in trees displaying crown shyness was succesfully quantified using a 3-D surface complementarity metric adopted from molecular biology. Crown surface complementarity showed a positive relationship to tree slenderness, similar to other metrics used for measuring crown shyness. The 3-D metric developed in this study revealed how trees adapt the shape of their crowns to those of adjacent trees and how this is linked to the slenderness of the trees.
Changes in Severe Acute Respiratory Syndrome Coronavirus 2 Seroprevalence Over Time in 10 Sites in the United States, March–August, 2020
Authors: Lim Travis , Delorey Mark , Bestul Nicolette , Johannson Michael A , Reed Carrie , Hall Aron J , Fry Alicia M , Edens Chris , Semenova Vera , Li Han , Browning Peter , Desai Rita , Epperson Monica , Jia Tao , Thornburg Natalie J , Schiffer Jarad , Havers Fiona P
Published: February 2021

Background

Monitoring of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody prevalence can complement case reporting to inform more accurate estimates of SARS-CoV-2 infection burden, but few studies have undertaken repeated sampling over time on a broad geographic scale.

Methods

We performed serologic testing on a convenience sample of residual serum obtained from persons of all ages, at 10 sites in the United States from 23 March through 14 August 2020, from routine clinical testing at commercial laboratories. We standardized our seroprevalence rates by age and sex, using census population projections and adjusted for laboratory assay performance. Confidence intervals were generated with a 2-stage bootstrap. We used bayesian modeling to test whether seroprevalence changes over time were statistically significant.

Results

Seroprevalence remained below 10% at all sites except New York and Florida, where it reached 23.2% and 13.3%, respectively. Statistically significant increases in seroprevalence followed peaks in reported cases in New York, South Florida, Utah, Missouri, and Louisiana. In the absence of such peaks, some significant decreases were observed over time in New York, Missouri, Utah, and Western Washington. The estimated cumulative number of infections with detectable antibody response continued to exceed reported cases in all sites.

Conclusions

Estimated seroprevalence was low in most sites, indicating that most people in the United States had not been infected with SARS-CoV-2 as of July 2020. The majority of infections are likely not reported. Decreases in seroprevalence may be related to changes in healthcare-seeking behavior, or evidence of waning of detectable anti–SARS-CoV-2 antibody levels at the population level. Thus, seroprevalence estimates may underestimate the cumulative incidence of infection.
The ghosts of parasitism past: lingering frontline anti-brood parasite defenses in a former host
Authors: Chaumont Matthew H J , Langmore Naomi E , Welbergen Justin A
Published: February 2021

Coevolutionary arms races between brood parasites and hosts provide tractable systems for understanding antagonistic coevolution in nature; however, little is known about the fate of frontline antiparasite defenses when the host “wins” the coevolutionary arms race. By recreating bygone species interactions, using artificial parasitism experiments, lingering defensive behaviors that evolved in the context of parasitism can be understood and may even be used to identify the unknown agent of parasitism past. Here we present the first study of this type by evaluating lingering “frontline” nest defenses that have evolved to prevent egg laying in a former brood parasite host. The Australian reed warbler Acrocephalus australis is currently not parasitized but is known to exhibit fine-tuned egg discrimination—a defensive behavior indicative of a past brood parasite–host arms race and common in closely related parasitized species. Here, using 3D-printed models of adult brood parasites, we examined whether the Australian reed warbler also exhibits frontline defenses to adult brood parasites, and whether we could use these defenses to identify the warbler’s “ghost of parasitism past.” Our findings provide evidence that the Australian reed warbler readily engages in frontline defenses that are considered adaptive specifically in the context of brood parasitism. However, individuals were unable to discriminate between adults of different brood parasite species at their nest. Overall, our results demonstrate that despite a relaxation in selection, defenses against brood parasitism can be maintained across multiple stages of the host’s nesting cycle, and further suggest that, in accordance with previous findings, that learning may be important for fine-tuning frontline defense.
Secretome analysis as a tool to elucidate bacterial contamination influence during second-generation ethanol production in a Melle-Boinot process
Authors: Collograi Karen Cristina , Pereira Isabela de Oliveira , Neitzel Thiago , Martinez-Jimenez Fernan David , da Costa Aline Carvalho , Ienczak Jaciane Lutz
Published: February 2021

Melle-boinot fermentation process can be used to increase the ethanol productivity in second-generation ethanol process (2G). However, bacterial contamination can result in decreased ethanol production and sugars consumption. The available literature on microbial contamination in the 2G at the secretome level, microbial interactions and their impacts on ethanol production are scarce. In this context, the cultivation of Spathaspora passalidarum was studied in pure and co-culture with Lactobacillus fermentum under conditions that mimic the Melle-boinot process. Glucose consumption and ethanol production by S. passalidarum were not affected by bacterial contamination. Xylose consumption was higher in pure culture (11.54 ± 2.62, 16.23 ± 1.76 and 6.50 ± 1.68 g) than in co-culture fermentation (11.89 ± 0.38, 7.29 ± 0.49 and 5.54 ± 2.63 g) in cycle 2. The protein profile of the fermented broth was similar in pure and co-culture fermentation. The low effect of L. fermentum on fermentation and protein profile may be associated with the inhibition of the bacteria by the low nutrient fermentation broth, with centrifugation and/or with sulfuric acid washing. Thereby, considering that research on microbial contamination in the 2G fermentation process is very limited, particularly at the omics level, these findings may contribute to the lignocellulosic biomass fermentation industry.
CFD analysis of jet flows ejected from different nozzles
Authors: Atmaca Mustafa , Çetin Berkay , Ezgi Cüneyt , Kosa Ergin
Published: February 2021

Nozzles are widely used to control the rate of flow, speed, direction, mass, shape and pressure of the stream in connection with many different engineering applications. This paper presents the performance predicted by a computational fluid dynamic (CFD) model, which are 3D models that utilize parametric analysis, realizable k-epsilon turbulence models and experimental measurement for a jet. Jet flows are ejected from three different slot nozzles: round-shaped nozzle, rectangular-shaped nozzle and 2D-contoured nozzle. In this numerical study, velocities of free jets have been predicted for different axial distances from the nozzle exit in the range of $0.2\le z/B\le 12$ when center velocity at the nozzle exit. CFD simulation results are compared to experimental results from literature. These results are consistent with the existing experiments.
ASAS-NANP SYMPOSIUM: Applications of machine learning for livestock body weight prediction from digital images
Authors: Wang Zhuoyi , Shadpour Saeed , Chan Esther , Rotondo Vanessa , Wood Katharine M , Tulpan Dan
Published: February 2021

Monitoring, recording, and predicting livestock body weight (BW) allows for timely intervention in diets and health, greater efficiency in genetic selection, and identification of optimal times to market animals because animals that have already reached the point of slaughter represent a burden for the feedlot. There are currently two main approaches (direct and indirect) to measure the BW in livestock. Direct approaches include partial-weight or full-weight industrial scales placed in designated locations on large farms that measure passively or dynamically the weight of livestock. While these devices are very accurate, their acquisition, intended purpose and operation size, repeated calibration and maintenance costs associated with their placement in high-temperature variability, and corrosive environments are significant and beyond the affordability and sustainability limits of small and medium size farms and even of commercial operators. As a more affordable alternative to direct weighing approaches, indirect approaches have been developed based on observed or inferred relationships between biometric and morphometric measurements of livestock and their BW. Initial indirect approaches involved manual measurements of animals using measuring tapes and tubes and the use of regression equations able to correlate such measurements with BW. While such approaches have good BW prediction accuracies, they are time consuming, require trained and skilled farm laborers, and can be stressful for both animals and handlers especially when repeated daily. With the concomitant advancement of contactless electro-optical sensors (e.g., 2D, 3D, infrared cameras), computer vision (CV) technologies, and artificial intelligence fields such as machine learning (ML) and deep learning (DL), 2D and 3D images have started to be used as biometric and morphometric proxies for BW estimations. This manuscript provides a review of CV-based and ML/DL-based BW prediction methods and discusses their strengths, weaknesses, and industry applicability potential.
Functional diversity vs. monotony: the effect of a multiforage diet as opposed to a single forage diet on animal intake, performance, welfare, and urinary nitrogen excretion
Authors: Garrett Konagh , Beck Matt R , Marshall Cameron J , Fleming Anita E , Logan Chris M , Maxwell Thomas M R , Greer Andrew W , Gregorini Pablo
Published: February 2021

The objective of this study was to determine the effect of offering animals a multiforage choice (MF) of fresh herbages on dry matter intake (DMI), live weight gain, and animal welfare, in comparison with a monotonous diet of ryegrass (Lolium perenne L.). Twenty ram lambs (30.5 ± 0.9 kg initial live weight; mean ± SEM), were randomly allocated to either a diet consisting of diverse MF choice or a single forage ryegrass (SF) diet (n = 10 per treatment) for 35 d. Both diets were fed ad libitum; however, the MF diet was composed of set dry matter ratios of 24% chicory (Cichorium intybus L.), 30% lucerne (Medicago sativa L.), 25% plantain (Plantago lanceolata L.), and 21% ryegrass. The DMI of the MF lambs was 48% greater (P < 0.01) and the within animal day-to-day coefficient of variation (CV) of intake was 26% lower (P < 0.01) than the SF lambs. The average daily gain (ADG) of lambs offered the MF diet was 92% greater (P < 0.01) than the lambs offered the SF diet. The within-animal day-to-day CV of intake was negatively related to ADG (r = −0.59; P < 0.01). The MF lamb’s urinary N concentration was 30% lower (P < 0.01) than that of the SF lambs. The SF lambs spent more time (P < 0.05) exhibiting stereotypic behaviors in the afternoon and spent more time observing other animals than the MF. Overall, allocating an MF choice of fresh herbages as opposed to a single forage diet of ryegrass increases DMI and thereby animal performance, while potentially reducing urinary N excretion.
Effect of Lactic Acid Supplementation on the Growth and Reproduction of Bombyx mori (Lepidopteria: Bombycidae)
Authors: He Zhen , Fang Yang , Li De-Chen , Chen Deng-Song , Wu Fan
Published: February 2021

Lactic acid is widely used in the food, drugs, cosmetics, and other industries to maintain the microbial stability of low-pH products. However, it is unclear whether lactic acid can affect silkworm (Bombyx mori) growth and reproduction. This study investigated the effects of lactic acid on the growth and reproduction of the silkworm. We analyzed the growth, cocoon quality, and reproductive performance of fifth instar larvae fed on mulberry leaves saturated with different concentrations (0.01, 0.1, 1, and 10%) of lactic acid and the control. Results showed that 0.01, 0.1, and 1% lactic acid supplementation positively affects growth and female cocoon quality, with increased larval weight and female cocoon shell weight compared to the control group. In contrast, 10% lactic acid was toxic to the larvae and significantly decreased growth, leading to larval death. Our study provides a basic reference for the optimal amount of preservatives. In addition, this study can be a desirable intervention for sericulturists and can play an important role in getting high return from silkworm-rearing activities.
Metachronous multiple pulmonary nodules 9 years after esophagectomy: a case report
Authors: Hara Kantaro , Matsuda Yumi , Furukawa Nao , Nagano Kohshi
Published: February 2021

A 79-year-old man was referred to our hospital for further examination. He had undergone radical esophagectomy with right thoracotomy 9 years ago. Four cycles of chemotherapy (CDDP +5-FU) were also performed for him. Eight years after esophagectomy, two nodules were identified in the upper lobe of the right lung on chest computed tomography (CT). Owing to the possibility of new primary lung cancer, partial resection was performed. Histopathological examination revealed squamous cell carcinoma. One year and two months later, follow-up chest CT scan revealed a nodule shadow of 1.5 cm in the left apex and a nodule shadow of 0.9 cm below the S9 pleura. Hence, partial left lung resection was performed. Five months after left lung resection, a metastatic liver tumor was found on abdominal CT and left lobectomy of the liver was performed. One year after hepatectomy, the patient died due to peritoneal dissemination.
Dangers that Lurk in a Kiss: Quarantining the American Mouth, 1890–1920
Authors: Baldwin Peter C
Published: February 2021

Affluent women, with the inconsistent support of some medical experts, led an early twentieth-century push to stop the practice of kissing. Imogene Rechtin of Cincinnati and likeminded activists argued that all forms of kissing spread harmful bacteria. The anti-kissing campaign was part of a larger effort to impose stricter discipline over the mouth, which thanks to recent advances in bacteriology had been identified as a dangerous vector of disease. Shaped by the Progressive Era inclination to solve problems through strategies of spatial separation, the effort to “quarantine” the American mouth involved disrupting social practices such as sharing the communion chalice and using a common cup at drinking fountains. The anti-kissing movement also attempted to protect women from unsolicited social kisses from other women and uninvited erotic kisses by men. Though public health officials strongly supported other mouth reforms, they opposed the anti-kissing campaign, largely on the nonmedical grounds that it was an impossible rejection of human sexuality. Then as now, public health arguments over mouth practices have been shaped by deeper battles over individual autonomy and the obligations of the individual to society.
Risk of Nonresponse Bias and the Length of the Field Period in a Mixed-Mode General Population Panel
Authors: Struminskaya Bella , Gummer Tobias
Published: February 2021

Survey researchers are often confronted with the question of how long to set the length of the field period. Longer fielding time might lead to greater participation yet requires survey managers to devote more of their time to data collection efforts. With the aim of facilitating the decision about the length of the field period, we investigated whether a longer fielding time reduces the risk of nonresponse bias to judge whether field periods can be ended earlier without endangering the performance of the survey. By using data from six waves of a probability-based mixed-mode (online and mail) panel of the German population, we analyzed whether the risk of nonresponse bias decreases over the field period by investigating how day-by-day coefficients of variation develop during the field period. We then determined the optimal cut-off points for each mode after which data collection can be terminated without increasing the risk of nonresponse bias and found that the optimal cut-off points differ by mode. Our study complements prior research by shifting the perspective in the investigation of the risk of nonresponse bias to panel data as well as to mixed-mode surveys, in particular. Our proposed method of using coefficients of variation to assess whether the risk of nonresponse bias decreases significantly with each additional day of fieldwork can aid survey practitioners in finding the optimal field period for their mixed-mode surveys.
Travel-associated multidrug-resistant organism acquisition and risk factors among US military personnel
Authors: Buchek Gregory , Mende Katrin , Telu Kalyani , Kaiser Susan , Fraser Jamie , Mitra Indrani , Stam Jason , Lalani Tahaniyat , Tribble David , Yun Heather C
Published: February 2021

Background

International travel is a risk factor for incident colonization with extended spectrum beta-lactamase (ESBL)-producing organisms. These and other multidrug-resistant (MDR) bacteria are major pathogens in combat casualties. We evaluated risk factors for colonization with MDR bacteria in US military personnel travelling internationally for official duty.

Methods

TravMil is a prospective observational study enrolling subjects presenting to military travel clinics. We analysed surveys, antimicrobial use data, and pre- and post-travel perirectal swabs in military travellers to regions outside the continental USA, Canada, Western or Northern Europe, or New Zealand, presenting to one clinic from 12/2015 to 12/2017. Recovered Gram-negative isolates underwent identification and susceptibility testing (BD Phoenix). Characteristics of trip and traveller were analysed to determine risk factors for MDR organism colonization.

Results

110 trips were planned by 99 travellers (74% male, median age 38 years [IQR 31, 47.25]); 72 trips with returned pre- and post-travel swabs were completed by 64 travellers. Median duration was 21 days (IQR 12.75, 79.5). 17% travelled to Mexico/Caribbean/Central America, 15% to Asia, 57% to Africa and 10% to South America; 56% stayed in hotels and 50% in dormitories/barracks. Travellers used doxycycline (15%) for malaria prophylaxis, 11% took an antibiotic for travellers’ diarrhoea (TD) treatment (fluoroquinolone 7%, azithromycin 4%). Incident MDR organism colonization occurred in 8 travellers (incidence density 3.5/1000 travel days; cumulative incidence 11% of trips [95% CI: 4–19%]), all ESBL-producing Escherichia coli. A higher incidence of ESBL-producing E. coli acquisition was associated with travel to Asia (36% vs 7%, P = 0.02) but not with travel to other regions, TD or use of antimicrobials. No relationship was seen between fluoroquinolone or doxycycline exposure and resistance to those antimicrobials.

Conclusions

Incident colonization with MDR organisms occurs at a lower rate in this military population compared with civilian travellers, with no identified modifiable risk factors, with highest incidence of ESBL acquisition observed after South Asia travel.
A spectroscopically confirmed Gaia-selected sample of 318 new young stars within ∼200 pc
Authors: Žerjal Maruša , Rains Adam D , Ireland Michael J , Zhou George , Kammerer Jens , Wallace Alex , Orenstein Brendan J , Nordlander Thomas , Abbot Harrison , Chang Seo-Won
Published: February 2021

In the Gaia era, the majority of stars in the Solar neighbourhood have parallaxes and proper motions precisely determined while spectroscopic age indicators are still missing for a large fraction of low-mass young stars. In this work, we select 756 overluminous late K and early M young star candidates in the southern sky and observe them over 64 nights with the ANU 2.3-m Telescope at Siding Spring Observatory using the Echelle (R = 24 000) and Wide Field spectrographs (WiFeS, R = 3000–7000). Our selection is kinematically unbiased to minimize the preference against low-mass members of stellar associations that dissipate first and to include potential members of diffuse components. We provide measurements of Hα and calcium H&K emission, as well as of Li i 6708 Å in absorption. This enables identification of stars as young as  10–30 Myr – a typical age range for stellar associations. We report on 346 stars showing detectable lithium absorption, 318 of which are not included in existing catalogues of young stars. We also report 125 additional stars in our sample presenting signs of stellar activity indicating youth but with no detectable lithium. Radial velocities are determined for WiFeS spectra with a precision of 3.2 km s−1 and 1.5 km s−1 for the Echelle sample.
Fanaroff–Riley classification of radio galaxies using group-equivariant convolutional neural networks
Authors: Scaife Anna M M , Porter Fiona
Published: February 2021

Weight sharing in convolutional neural networks (CNNs) ensures that their feature maps will be translation-equivariant. However, although conventional convolutions are equivariant to translation, they are not equivariant to other isometries of the input image data, such as rotation and reflection. For the classification of astronomical objects such as radio galaxies, which are expected statistically to be globally orientation invariant, this lack of dihedral equivariance means that a conventional CNN must learn explicitly to classify all rotated versions of a particular type of object individually. In this work we present the first application of group-equivariant convolutional neural networks to radio galaxy classification and explore their potential for reducing intra-class variability by preserving equivariance for the Euclidean group E(2), containing translations, rotations, and reflections. For the radio galaxy classification problem considered here, we find that classification performance is modestly improved by the use of both cyclic and dihedral models without additional hyper-parameter tuning, and that a D16 equivariant model provides the best test performance. We use the Monte Carlo Dropout method as a Bayesian approximation to recover epistemic uncertainty as a function of image orientation and show that E(2)-equivariant models are able to reduce variations in model confidence as a function of rotation.
GAMA/DEVILS: constraining the cosmic star formation history from improved measurements of the 0.3–2.2  μm extragalactic background light
Authors: Koushan Soheil , Driver Simon P , Bellstedt Sabine , Davies Luke J , Robotham Aaron S G , Lagos Claudia del P , Hashemizadeh Abdolhosein , Obreschkow Danail , Thorne Jessica E , Bremer Malcolm , Holwerda B W , Hopkins Andrew M , Jarvis Matt J , Siudek Malgorzata , Windhorst Rogier A
Published: February 2021

We present a revised measurement of the optical extragalactic background light (EBL), based on the contribution of resolved galaxies to the integrated galaxy light (IGL). The cosmic optical background radiation (COB), encodes the light generated by star formation, and provides a wealth of information about the cosmic star formation history (CSFH). We combine wide and deep galaxy number counts from the Galaxy And Mass Assembly survey (GAMA) and Deep Extragalactic VIsible Legacy Survey (DEVILS), along with the Hubble Space Telescope (HST) archive and other deep survey data sets, in nine multiwavelength filters to measure the COB in the range from 0.35  μm to 2.2  μm. We derive the luminosity density in each band independently and show good agreement with recent and complementary estimates of the optical-EBL from very high-energy (VHE) experiments. Our error analysis suggests that the IGL and γ-ray measurements are now fully consistent to within $\sim 10{{\ \rm per\ cent}}$, suggesting little need for any additional source of diffuse light beyond the known galaxy population. We use our revised IGL measurements to constrain the CSFH, and place amplitude constraints on a number of recent estimates. As a consistency check, we can now demonstrate convincingly, that the CSFH, stellar mass growth, and the optical-EBL provide a fully consistent picture of galaxy evolution. We conclude that the peak of star formation rate lies in the range 0.066–0.076 M⊙ yr−1 Mpc−3 at a lookback time of 9.1 to 10.9 Gyr.
Absorption effects in the blazar’s γ-ray spectra due to luminous stars crossing the jet
Authors: Bednarek W , Sitarek J
Published: February 2021

γ-ray emission in active galaxies is likely produced within the inner jet, or in the close vicinity of the supermassive black hole (SMBH) at sub-parsec distances. γ-rays have to pass through the surrounding massive stellar cluster in which luminous stars can accidentally appear close to the observer’s line of sight. In such a case, soft radiation of massive stars can create enough target for transient absorption of the γ-rays in multi-GeV to TeV energy range. We consider the effect of such stellar encounters on the γ-ray spectrum produced within the massive stellar cluster surrounding a central SMBH. We predict characteristic, time-dependent effects on the γ-ray spectra due to the encounter with the single luminous star and also stellar binary system. We conclude that during the encounter, the γ-ray spectrum of an active galaxy should steepen at tens of GeV and harden in the range of hundreds of GeV. As an example, we consider such effects on the spectra observed from a typical blazar, 1ES 1959+650 (in an active state) and also in the case of a radio galaxy M87 (in a low state). It is shown that observation of such transient characteristic features in the γ-ray spectra, observed from blazars and radio galaxies, lays within the sensitivity of the future Cherenkov Telescope Array.
Effect of separate initial conditions on the lyman-α forest in simulations
Authors: Fernandez M A , Bird Simeon , Upton Sanderbeck Phoebe
Published: February 2021

Using a set of high resolution simulations, we quantify the effect of species-specific initial transfer functions on probes of the intergalactic medium (IGM) via the Lyman-α forest. We focus on redshifts 2–6, after H i reionization. We explore the effect of these initial conditions on measures of the thermal state of the low density IGM: the curvature, Doppler width cutoff, and Doppler width distribution. We also examine the matter and flux power spectrum, and potential consequences for constraints on warm dark matter models. We find that the curvature statistic is at most affected at the $\approx 2{{\ \rm per\ cent}}$ level at z = 6. The Doppler width cutoff parameters are affected by $\approx 5{{\ \rm per\ cent}}$ for the intercept, and $\approx 8{{\ \rm per\ cent}}$ for the fit slope, though this is subdominant to sample variation. The Doppler width distribution shows a $\approx 30{{\ \rm per\ cent}}$ effect at z = 3, however the distribution is not fully converged with simulation box size and resolution. The flux power spectrum is at most affected by $\approx 5{{\ \rm per\ cent}}$ at high redshift and small scales. We discuss numerical convergence with simulation parameters.
Feedback factory: multiple faint radio jets detected in a cluster at z = 2
Authors: Kalita Boris S , Daddi Emanuele , Coogan Rosemary T , Delvecchio Ivan , Gobat Raphael , Valentino Francesco , Strazzullo Veronica , Tremou Evangelia , Gómez-Guijarro Carlos , Elbaz David , Finoguenov Alexis
Published: February 2021

We report the detection of multiple faint radio sources, that we identify as active galactic nucleus (AGN) jets, within CLJ1449+0856 at z = 2 using 3 GHz Very Large Array observations. We study the effects of radio-jet-based kinetic feedback at high redshifts, which has been found to be crucial in low-redshift clusters to explain the observed thermodynamic properties of their intracluster medium (ICM). We investigate this interaction at an epoch featuring high levels of AGN activity and a transitional phase of ICM in regards to the likelihood of residual cold gas accretion. We measure a total flux of $\rm 30.6 \pm 3.3\, \mu Jy$ from the six detected jets. Their power contribution is estimated to be $1.2 \, (\pm 0.6)\, \times 10^{44} \, \rm erg\, s^{-1}$, although this value could be up to $4.7 \, \times 10^{44} \, \rm erg\, s^{-1}$. This is a factor of ∼0.25–1.0 of the previously estimated instantaneous energy injection into the ICM of CLJ1449+0856 from AGN outflows and star formation that have already been found to be sufficient in globally offsetting the cooling flows in the cluster core. In line with the already detected abundance of star formation, this mode of feedback being distributed over multiple sites, contrary to a single central source observed at low redshifts, points to accretion of gas into the cluster centre. This also suggests a ‘steady state’ of the cluster featuring non-cool-core-like behaviour. Finally, we also examine the total infrared–radio luminosity ratio for the known sample of galaxies within the cluster core and find that dense environments do not have any serious consequence on the compliance of galaxies to the infrared–radio correlation.
Physical modelling of the circumstellar material in the early-type active binary HH Carinae
Authors: Bakış H , Köseoglu D T , Bakış V , Nitschelm C , Eker Z
Published: February 2021

High-resolution spectra ($R\sim 48\, 000$) of the massive binary system HH Carinae have been analysed. Precise absolute parameters were derived from a simultaneous solution of the radial velocities and the light curves. The primary component is found to be an O9-type main-sequence star with a temperature of 33 500 K, while the secondary component is a B0-type giant/subgiant star with a temperature of 27 500 K. An analysis of the spectroscopic and photometric data has shown that the primary component rotates at a speed of vrot1 = 220 km s−1, which is three times faster than the synchronous rotation, while the secondary component synchronously rotates with the orbit at a speed of vrot2 = 150 km s−1. The distance to the system and the velocity of the centre of mass are determined as d = 4.6 ± 0.8 kpc and Vγ = –16 km s−1, respectively. The distance of the system is in agreement with the most probable Gaia distance of $4.9^{+0.9}_{-0.7}$ kpc and the distance in the latest data release (DR3) of 4.4 ± 0.3. Emission structures at the Hα region were modelled using the code shellspec where the derived absolute parameters of the components have been considered. Because the components are massive stars, mass loss as a result of stellar winds is expected. Produced models confirm that the components do indeed have strong stellar winds and there is mass transfer from the secondary to the primary. Stellar winds and the gas stream between the components have been modelled as a hot shell around the system, with a temperature of ∼22 000 K. Models also indicate that the interaction between the wind and the gas stream causes the formation of a high-temperature (100 000 K) impact region.
Clinical Implications of Size of Cavities in Patients With Nontuberculous Mycobacterial Pulmonary Disease: A Single-Center Cohort Study
Authors: Kang Hye-Rin , Hwang Eui Jin , Kim Sung A , Choi Sun Mi , Lee Jinwoo , Lee Chang-Hoon , Yim Jae-Joon , Kwak Nakwon
Published: February 2021

Background

The presence of cavities is associated with unfavorable prognosis in patients with nontuberculous mycobacterial pulmonary disease (NTM-PD). However, little is known about the characteristics of such cavities and their impact on clinical outcomes. The aim of this study was to investigate the size of cavities and their implications on treatment outcomes and mortality in patients with NTM-PD.

Methods

We included patients diagnosed with NTM-PD at Seoul National University Hospital between January 1, 2007, and December 31, 2018. We measured the size of cavities on chest computed tomography scans performed at the time of diagnosis and used multivariable logistic regression and Cox proportional hazards regression analysis to investigate the impact of these measurements on treatment outcomes and mortality.

Results

The study cohort comprised 421 patients (noncavitary, n = 329; cavitary, n = 92) with NTM-PD. During a median follow-up period of 49 months, 118 (35.9%) of the 329 patients with noncavitary and 64 (69.6%) of the 92 patients with cavitary NTM-PD received antibiotic treatment. Cavities >2 cm were associated with worse treatment outcomes (adjusted odds ratio, 0.41; 95% CI, 0.17–0.96) and higher mortality (adjusted hazard ratio, 2.52; 95% CI, 1.09–5.84), while there was no difference in treatment outcomes or mortality between patients with cavities ≤2 cm and patients with noncavitary NTM-PD.

Conclusions

Clinical outcomes are different according to the size of cavities in patients with cavitary NTM-PD; thus, the measurement of the size of cavities could help in making clinical decisions.
What do Consumers Consider Before They Choose? Identification from Asymmetric Demand Responses
Authors: Abaluck Jason , Adams-Prassl Abi
Published: February 2021

Consideration set models generalize discrete-choice models by relaxing the assumption that consumers consider all available options. Determining which options were considered has previously required either survey data or restrictions on how attributes affect consideration or utility. We provide an alternative route. In full-consideration models, choice probabilities satisfy a symmetry property analogous to Slutsky symmetry in continuous-choice models. This symmetry breaks down in consideration set models when changes in characteristics perturb consideration. We show that consideration probabilities are constructively identified from the resulting asymmetries. We validate our approach in a lab experiment where consideration sets are known and then apply our framework to study a “smart default” policy in Medicare Part D, wherein consumers are automatically reassigned to lower-cost prescription drug plans with the option of opting out. Full-consideration models imply that such a policy will be ineffective because consumers will opt out to avoid switching costs. Allowing for inattention, we find that defaulting all consumers to lower-cost options produces negligible welfare benefits on average, but defaulting only consumers who would save at least $300 produces large benefits.
Hydration Modulates G‐Protein‐Coupled Receptor Signaling
Authors: Fried Steven D.E. , Eitel Anna R. , Weerasinghe Nipuna , Norris Carolanne E. , Vos Margaret R. , Somers Johnathan D. , Fitzwater Gabrielle I. , Pitman Michael C. , Struts Andrey V. , Perera Suchithranga M.D.C. , Brown Michael F.
Published: February 2021

Rhodopsin is the G‐protein‐coupled receptor (GPCR) responsible for scotopic vision in the retina. Up to this point, the role of water in the activation of GPCRs has remained largely unknown. Recently, however, nanosecond molecular dynamics simulations have revealed an influx of bulk water into rhodopsin during activation [1]. Utilizing rhodopsin as a model GPCR, we tested the hypothesis that rhodopsin activation is hydration mediated using osmotic stress techniques. We subjected rhodopsin within its native lipid membranes to varying osmotic pressures induced by different‐sized polyethylene glycol polymers. UV‐Visible spectroscopy of the photoactivated rhodopsin system reveals the fraction of protein in the active metarhodopsin‐II (MII) conformation, the receptor state capable of activating the G‐protein. We discovered high‐molecular weight osmolytes uniformly favored the closed, inactive metarhodopsin‐I conformation by dehydration of the protein interior. By contrast, small osmolytes penetrated into the transducin binding cleft and stabilized the active MII conformation until a quantifiable saturation point. A universal osmotic response occurred in the limit of increasing osmolyte size and maximal polymer exclusion from rhodopsin. By measuring the thermodynamic dependence of the metarhodopsin equilibrium on osmotic pressure, we determined that rhodopsin activation is coupled to a bulk influx of 80–100 water molecules into the protein core with a substantial increase in compressibility. We propose a new model for the functional role of water in GPCR signal transduction, in which a wet‐dry cycling mechanism amplifies the activation of G‐proteins. Our results necessitate a new understanding of GPCR activation, in which the influx of water plays a critical role in establishing the active receptor conformation.

Support or Funding Information

This work was supported by the NIH (EY026041 and EY012049) and the NSF (MCB 1817862).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.