Publication bias in the social sciences Franco, Annie; Malhotra, Neil; Simonovits, Gabor
Science (American Association for the Advancement of Science),
09/2014, Letnik:
345, Številka:
6203
Journal Article
Recenzirano
We studied publication bias in the social sciences by analyzing a known population of conducted studies—221 in total—in which there is a full accounting of what is published and unpublished. We ...leveraged Time-sharing Experiments in the Social Sciences (TESS), a National Science Foundation–sponsored program in which researchers propose survey-based experiments to be run on representative samples of American adults. Because TESS proposals undergo rigorous peer review, the studies in the sample all exceed a substantial quality threshold. Strong results are 40 percentage points more likely to be published than are null results and 60 percentage points more likely to be written up. We provide direct evidence of publication bias and identify the stage of research production at which publication bias occurs: Authors do not write up and submit null findings.
An innovative microalgae harvesting technique was carried out under various anode/cathode (2/2, 4/4 and 6/6) configuration and at different voltage treatment (3, 6 and 10 V) to efficiently ...electroflocculate Chaetoceros calcitrans. This study was conducted to determine the optimal configuration of electrode units (Pb and Al) and voltage settings that could improve the quality of harvested paste in terms of nutritional value and metal contamination for its later use in aquaculture. The use of 6/6 electrodes achieved the shortest harvest time of 48 ± 1 min and the lowest Pb content (83.7 ± 0.3 ppm). In terms of voltage treatment, harvest time was inversely proportional to the voltage used. However, Pb content was significantly lowest in the paste produced using 3 V (41.78 ± 0.12 ppm), when compared to those harvested under 6 V (304.35 ± 0.79 ppm) and 10 V (343.90 ± 0.91 ppm) treatment. Likewise, Pb residues in the resulting effluent are also lowest (0.245 ± 0 ppm) with 3 V treatments. C. calcitrans paste can be resuspended ≤6 months but with a lag phase of 3–4 days for use as starter culture. A 97% reduction in Pb content of C. calcitrans paste and 77% reduction in Pb content were obtained in Artemia (7.8%) fed C. calcitrans paste.
This study evaluated the suitability of five diatom species (
Amphora
sp.,
Cocconeis
sp.,
Navicula ramosissima
,
Nitzschia
sp., and
Tryblionella
sp.) as food to abalone
Haliotis asinina
early ...juveniles (5-mm shell length). Grazing periodicity, grazing rate, and feeding preference were measured; at the same time, abalone gut content was examined. Grazing incidence appeared to be continuous with significantly higher grazing intensity observed at nighttime from 6 p.m. to 10 p.m. (79%) than at daytime from 10 a.m. to 2 p.m. (40%) (
p
< 0.05). Grazing rates from 6 p.m. to 10 p.m. were significantly higher on
N. ramosissima
(1.6 × 10
5
) among diatom species but was not statistically different from
Cocconeis
sp. (1.1 × 10
5
) (
p
> 0.05). Broken cells of
Amphora
sp. (22%) were significantly higher in the gut of
H. asinina
compared to
Cocconeis
sp. (2.8%),
N. ramosissima
, (1.8%), and
Tryblionella
sp. (0.2%) although the abundance of
Nitzschia
sp. (6%) was not significantly different from
Amphora
sp. (
p
> 0.05). Early juveniles showed significant preference for
Cocconeis
sp. (18.6%), followed by
Nitzschia
sp. (16.2%),
N. ramosissima
(13.9%), and
Amphora
sp. (13.4%), with the least preference for
Tryblionella
sp. (7.8%). Survival of
H. asinina
was similar in 4 diatom species (46–71%) except in
Tryblionella
sp. (8–12%). These findings suggest that diatom species
Cocconeis
sp.,
Nitzschia
sp.,
Amphora
sp., and
N. ramosissima
are the suitable live food for
H. asinina
early juveniles. Knowledge from this study would contribute to the development of a feeding protocol that would maximize production of
H. asinina
early juveniles in the hatchery.
An innovative microalgae harvesting technique using electroflocculation was carried out at different voltage treatments (4, 7, and 9 V) using a fabricated voltage regulator and compared with ...harvesting by electroflocculation at 12 V using a car battery to efficiently electroflocculate
Tetraselmis tetrathele
. This study was conducted to determine the ideal voltage settings that could improve the quality of harvested paste in terms of nutritional value and metal contamination for its later use in aquaculture. The use of 7 V achieved low Pb content producing the best harvest biomass (1.4 kg, 87 min) which is comparable to the harvest biomass (1.7 kg, 68 min) using a 12 V car battery. Storage of
T. tetrathele
paste is best done in a chiller (2 ± 1 °C) rather than a freezer (-20 ± -4 °C) for ease in reactivation and maintaining higher cell viability for later use as a starter in aquaculture. Storage in a chiller allows
T. tetrathele
paste to be resuspended after six months and used as a starter culture.
The optimum culture conditions of the local strain
Chaetoceros calcitrans
were determined to improve biomass and reduce cost of production. Under outdoor culture conditions, higher cell density was ...attained when the cultures were enriched with Tungkang Marine Research Laboratory (TMRL) medium composed of cheap technical grade reagents and cultured at 25 g L
−1
salinity. The cultures were lighted with two 40 W cool-white GE fluorescent tubes (24–35 μmol photon m
−2
s
−1
). Using semi-continuous culture system under established optimum culture conditions,
C. calcitrans
can be re-cultured thrice and concentrated at each culture cycle using electrolytic flocculation method to produce 4.6 kg m
−3
of diatom paste. The viability of concentrated
C. calcitrans
after 3 months of storage was comparable to live diatom cells. Simple preservation technique by low-temperature storage is convenient for storing algal concentrates for use as starter cultures and for feeding invertebrates. The paste costs USD 8.24 kg
−1
inclusive of the assets and flocculation materials for culturing and harvesting the diatom, respectively. This study established the suitable conditions for mass culture of
C. calcitrans
and produced concentrated diatoms in paste form that is readily available for aquaculture hatcheries at a lower cost.
Increases in racial minority populations are profoundly reshaping the composition of the American electorate, and multiracial identifiers are one of the fastest growing groups. Yet little is known ...about the political ideology and policy preferences of Americans who identify with more than one race. We address this gap here by examining the political views of the two biggest US multiracial groups—White-Asians and White-Blacks. We also advance prior work by assessing the role that linked fate, racial group closeness, and race salience play in explaining multiracials’ political attitudes. Leveraging the largest national political survey of multiracial adults to date, we find that White-Asian and White-Black multiracials are on the whole more progressive than Whites, expressing levels of linked fate and social and racial attitudes that are comparable to those of their minority race. We argue that the growth in these multiracial populations seems most likely to benefit the Democratic Party.
Many scholars have raised concerns about the credibility of empirical findings in psychology, arguing that the proportion of false positives reported in the published literature dramatically exceeds ...the rate implied by standard significance levels. A major contributor of false positives is the practice of reporting a subset of the potentially relevant statistical analyses pertaining to a research project. This study is the first to provide direct evidence of selective underreporting in psychology experiments. To overcome the problem that the complete experimental design and full set of measured variables are not accessible for most published research, we identify a population of published psychology experiments from a competitive grant program for which questionnaires and data are made publicly available because of an institutional rule. We find that about 40% of studies fail to fully report all experimental conditions and about 70% of studies do not report all outcome variables included in the questionnaire. Reported effect sizes are about twice as large as unreported effect sizes and are about 3 times more likely to be statistically significant.
The ability of the “green water” grow-out culture of the tiger shrimp
Penaeus monodon to prevent outbreaks of Luminous Vibriosis was investigated by screening associated isolates of bacteria, fungi, ...phytoplankton and fish skin mucus for anti-luminous
Vibrio metabolites. Among the 85 bacterial isolates tested, 63 (74%) caused +∼+++ inhibition of the
Vibrio harveyi pathogen after 24–48 h co-cultivation. The variation in growth inhibition rates of +, ++, and +++ were demonstrated by 15 (18%), 13 (15%), and 28 (33%) isolates, respectively, 24 h after treatment. Eight bacterial isolates showed consistently sustained maximum inhibition of luminous
Vibrio after 24 to 48 h exposure. The majority of these luminous
Vibrio inhibiting bacterial isolates were obtained from tilapia mucus and gut. In tests with fungi, 4 of 20 (20%) yeast isolates showed intracellular metabolites inhibitory to luminous
Vibrio. Among filamentous fungi, 5 of 45 (11%) isolates yielded intracellular metabolites while 3 of 41 (7%) isolates had extracellular metabolites inhibitory to luminous
Vibrio. These fungal isolates were identified as
Rhodotorula sp.,
Saccharomyces sp.,
Candida sp.,
Penicillium sp., mycelia sterilia, and two unidentified species. The microalgae,
Chaetoceros calcitrans and
Nitzchia sp., consistently demonstrated complete inhibition of luminous
Vibrio from 24 h and 48 h post exposure, respectively, and during the 7-day experiment.
Leptolyngbia sp. caused a 94–100% reduction of the luminous
Vibrio population from 10
4 to 10
1 cfu/ml 24 h post exposure which was sustained throughout the 10-day observation period. In contrast, the inhibitory effects of
Skeletonema costatum on luminous
Vibrio was bacteriostatic throughout the 7-day exposure while
Nannochlorum sp. did not significantly inhibit luminous
Vibrio. The skin mucus of jewel tilapia,
Tilapia hornorum, had no resident luminous bacteria and inhibited this bacterial pathogen in 6–48 h, which was proportionate to the 10
3 and 10
5 cfu/ml test concentrations of luminous
Vibrio. This study provides a scientific explanation that the effectiveness of the “green water” culture of tiger shrimp (
P. monodon) in preventing outbreaks of luminous Vibriosis among
P. monodon juveniles in grow-out ponds can be attributed to the presence of anti-luminous
Vibrio factors in the bacterial, fungal, phytoplankton microbiota and the skin mucus of tilapia associated with this novel technique of shrimp culture.
Despite the progress in the production of artificial diets for marine larvae, feeding during the early life stages of most aquaculture species still relies on live feeds such as rotifers. Advanced ...rotifer culture techniques are also available, however, in the Philippines, majority use batch cultures with fresh microalgae. These microalgae are prone to collapse resulting to inadequate supply of food for the rotifers that are fed to the larvae. Mangrove crab is one of the economically important aquaculture species in the country where mass seed production requires sufficient and steady supply of rotifers. Thus, here we examined the possibility of substituting fresh culture of green microalgae
Tetraselmis tetrathele
(FA) with flocculated
T. tetrathele
paste (FP) and commercially available
Tetraselmis
sp. (CP) as feed for rotifers (
Brachionus rotundiformis
) in the seed production of mangrove crab. Rearing of larvae was done until crab instar 1 (DOC 24) where growth and survival were taken to evaluate the viability of rotifers-fed microalgal paste. It was observed that the growth index (FA–6.93 ± 0.07; FP–6.91 ± 0.07; CP–6.96 ± 0.05) was similar for all treatments (
P
> 0.05) at termination. Comparable survival rates were noted for FA and FP at 1.08 ± 0.59% and 3.21 ± 2.09%, respectively (
P
> 0.05) while a significantly higher survival (
P
< 0.05) was recorded for CP at 7.73 ± 1.90%. These findings suggest that the algal paste tested are potential alternatives to fresh microalgae and this technique could benefit hatchery operators who lack the capital for setting up the facility and technical skills to maintain microalgae production.
Many critics raise concerns about the prevalence of 'echo chambers' on social media and their potential role in increasing political polarization. However, the lack of available data and the ...challenges of conducting large-scale field experiments have made it difficult to assess the scope of the problem
. Here we present data from 2020 for the entire population of active adult Facebook users in the USA showing that content from 'like-minded' sources constitutes the majority of what people see on the platform, although political information and news represent only a small fraction of these exposures. To evaluate a potential response to concerns about the effects of echo chambers, we conducted a multi-wave field experiment on Facebook among 23,377 users for whom we reduced exposure to content from like-minded sources during the 2020 US presidential election by about one-third. We found that the intervention increased their exposure to content from cross-cutting sources and decreased exposure to uncivil language, but had no measurable effects on eight preregistered attitudinal measures such as affective polarization, ideological extremity, candidate evaluations and belief in false claims. These precisely estimated results suggest that although exposure to content from like-minded sources on social media is common, reducing its prevalence during the 2020 US presidential election did not correspondingly reduce polarization in beliefs or attitudes.
