2,040 research outputs found
The Impact of Labor Constraints on the Farm Performance
Stricter immigration policies that affect an estimated 12 million unauthorized immigrants, 40% of whom are hired as farm workers, can potentially leave the highly labor-dependent organic farms more economically vulnerable. The displacement of unauthorized immigrants will expectedly create labor shortages. This study analyzes the impact of hiring constraints and changes in farm labor market conditions (due to stricter immigration policies) on the technical efficiency and financial performance of organic and conventional farms. A production function approach is used to analyze survey data that has a mix of organic and conventional farms in the Southeast region. Adjustment strategies to deal with labor shortage and providing workers with nonwage incentives have been determined to be an important determinant of farm income. Among the strategies, adjustment of wage and nonwage benefits were found to be the most effective but a combination of strategies is the most preferred approach to deal with labor shortage. Furthermore, we found productivity difference between farmers with labor shortage adjustment strategies and those who do not.Agricultural Finance, Production Economics, Productivity Analysis,
The influence of the Calbuco eruption on the 2015 Antarctic ozone hole in a fully coupled chemistry-climate model
Recent research has demonstrated that the concentrations of anthropogenic halocarbons have decreased in response to the worldwide phaseout of ozone depleting substances. Yet in 2015 the Antarctic ozone hole reached a historical record daily average size in October. Model simulations with specified dynamics and temperatures based on a reanalysis suggested that the record size was likely due to the eruption of Calbuco but did not allow for fully coupled dynamical or thermal feedbacks. We present simulations of the impact of the 2015 Calbuco eruption on the stratosphere using the Whole Atmosphere Community Climate Model with interactive dynamics and temperatures. Comparisons of the interactive and specified dynamics simulations indicate that chemical ozone depletion due to volcanic aerosols played a key role in establishing the record-sized ozone hole of October 2015. The analysis of an ensemble of interactive simulations with and without volcanic aerosols suggests that the forced response to the eruption of Calbuco was an increase in the size of the ozone hole by 4.5 × 10⁶ km²
ING116070: a study of the pharmacokinetics and antiviral activity of dolutegravir in cerebrospinal fluid in HIV-1-infected, antiretroviral therapy-naive subjects.
BackgroundDolutegravir (DTG), a once-daily, human immunodeficiency virus type 1 (HIV-1) integrase inhibitor, was evaluated for distribution and antiviral activity in cerebrospinal fluid (CSF).MethodsING116070 is an ongoing, single-arm, open-label, multicenter study in antiretroviral therapy-naive, HIV-1-infected adults. Subjects received DTG (50 mg) plus abacavir/lamivudine (600/300 mg) once daily. The CSF and plasma (total and unbound) DTG concentrations were measured at weeks 2 and 16. The HIV-1 RNA levels were measured in CSF at baseline and weeks 2 and 16 and in plasma at baseline and weeks 2, 4, 8, 12, and 16.ResultsThirteen white men enrolled in the study; 2 withdrew prematurely, 1 because of a non-drug-related serious adverse event (pharyngitis) and 1 because of lack of treatment efficacy. The median DTG concentrations in CSF were 18 ng/mL (range, 4-23 ng/mL) at week 2 and 13 ng/mL (4-18 ng/mL) at week 16. Ratios of DTG CSF to total plasma concentration were similar to the unbound fraction of DTG in plasma. Median changes from baseline in CSF (n = 11) and plasma (n = 12) HIV-1 RNA were -3.42 and -3.04 log10 copies/mL, respectively. Nine of 11 subjects (82%) had plasma and CSF HIV-1 RNA levels <50 copies/mL and 10 of 11 (91%) had CSF HIV-1 RNA levels <2 copies/mL at week 16.ConclusionsThe DTG concentrations in CSF were similar to unbound plasma concentrations and exceeded the in vitro 50% inhibitory concentration for wild-type HIV (0.2 ng/mL), suggesting that DTG achieves therapeutic concentrations in the central nervous system. The HIV-1 RNA reductions were similar in CSF and plasma. Clinical Trials Registration. NCT01499199
Quantifying the relative contribution of ante- and post-mortem factors to the variability in beef texture
This study aims to investigate the relative contribution of ante- and post-mortem factors to the final quality of beef. In all, 112
steers (four breed-crosses) were arranged in a 2 3 2 3 2 factorial experimental including production system, growth implant
and b-adrenergic agonist strategies. Carcasses were suspended by the Achilles tendon or the aitch bone and meat was aged for
2/6/13/21/27 days (longissimus muscle) or 2/27 days (semimembranosus muscle). Meat quality traits related to beef texture were
measured. Statistical analyses were developed including ante- and post-mortem factors and their relative contribution to the
variability observed for each measured trait was calculated. The main factor responsible for the variability in sarcomere length was
the suspension method (91.1%), which also influenced drip-loss (44.3%). Increasing the percentage of British breeds increased
(P , 0.05) the intramuscular fat content in longissimus muscle, but only when implants were not used. Thus, the breed-cross,
implant strategy and their interaction were responsible for .58% of the variability in this trait. The variability in instrumental and
sensory tenderness was mainly affected by post-mortem factors (carcass suspension, ageing time and their interaction), explaining
generally , 70% of the variability in these traits. Breed-cross was the second most important effect ( ,15%) when carcass
suspension was not considered in the model, but still ageing time was responsible for a much larger proportion of the variability
in tenderness (.45%). In conclusion, post-mortem handling of the carcasses may be much more effective in controlling beef
tenderness than pre-mortem strategies
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Tbx20 Is Required in Mid-Gestation Cardiomyocytes and Plays a Central Role in Atrial Development.
RationaleMutations in the transcription factor TBX20 (T-box 20) are associated with congenital heart disease. Germline ablation of Tbx20 results in abnormal heart development and embryonic lethality by embryonic day 9.5. Because Tbx20 is expressed in multiple cell lineages required for myocardial development, including pharyngeal endoderm, cardiogenic mesoderm, endocardium, and myocardium, the cell type-specific requirement for TBX20 in early myocardial development remains to be explored.ObjectiveHere, we investigated roles of TBX20 in midgestation cardiomyocytes for heart development.Methods and resultsAblation of Tbx20 from developing cardiomyocytes using a doxycycline inducible cTnTCre transgene led to embryonic lethality. The circumference of developing ventricular and atrial chambers, and in particular that of prospective left atrium, was significantly reduced in Tbx20 conditional knockout mutants. Cell cycle analysis demonstrated reduced proliferation of Tbx20 mutant cardiomyocytes and their arrest at the G1-S phase transition. Genome-wide transcriptome analysis of mutant cardiomyocytes revealed differential expression of multiple genes critical for cell cycle regulation. Moreover, atrial and ventricular gene programs seemed to be aberrantly regulated. Putative direct TBX20 targets were identified using TBX20 ChIP-Seq (chromatin immunoprecipitation with high throughput sequencing) from embryonic heart and included key cell cycle genes and atrial and ventricular specific genes. Notably, TBX20 bound a conserved enhancer for a gene key to atrial development and identity, COUP-TFII/Nr2f2 (chicken ovalbumin upstream promoter transcription factor 2/nuclear receptor subfamily 2, group F, member 2). This enhancer interacted with the NR2F2 promoter in human cardiomyocytes and conferred atrial specific gene expression in a transgenic mouse in a TBX20-dependent manner.ConclusionsMyocardial TBX20 directly regulates a subset of genes required for fetal cardiomyocyte proliferation, including those required for the G1-S transition. TBX20 also directly downregulates progenitor-specific genes and, in addition to regulating genes that specify chamber versus nonchamber myocardium, directly activates genes required for establishment or maintenance of atrial and ventricular identity. TBX20 plays a previously unappreciated key role in atrial development through direct regulation of an evolutionarily conserved COUPT-FII enhancer
Signalling through MyD88 drives surface expression of the mycobacterial receptors MCL (Clecsf8, Clec4d) and Mincle (Clec4e) following microbial stimulation
Acknowledgements We would like to thank the staff of the animal facility for their support and care for our animals. Funding was provided by the Wellcome Trust (102705) and Medical Research Council (UK) (MR/J004820/1) and a University of Aberdeen Studentship to BK.Peer reviewedPostprintPublisher PD
Gene regulatory changes underlie developmental plasticity in respiration and aerobic performance in highland deer mice
Phenotypic plasticity can play an important role in the ability of animals to tolerate environmental stress, but the nature and magnitude of plastic responses are often specific to the developmental timing of exposure. Here, we examine changes in gene expression in the diaphragm of highland deer mice (Peromyscus maniculatus) in response to hypoxia exposure at different stages of development. In highland deer mice, developmental plasticity in diaphragm function may mediate changes in several respiratory traits that influence aerobic metabolism and performance under hypoxia. We generated RNAseq data from diaphragm tissue of adult deer mice exposed to (1) life-long hypoxia (before conception to adulthood), (2) post-natal hypoxia (birth to adulthood), (3) adult hypoxia (6–8 weeks only during adulthood) or (4) normoxia. We found five suites of co-regulated genes that are differentially expressed in response to hypoxia, but the patterns of differential expression depend on the developmental timing of exposure. We also identified four transcriptional modules that are associated with important respiratory traits. Many of the genes in these transcriptional modules bear signatures of altitude-related selection, providing an indirect line of evidence that observed changes in gene expression may be adaptive in hypoxic environments. Our results demonstrate the importance of developmental stage in determining the phenotypic response to environmental stressors.
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