5,229 research outputs found

    A year in the life of a North Atlantic seabird: behavioural and energetic adjustments during the annual cycle

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    During their annual cycles, animals face a series of energetic challenges as they prioritise different life history events by engaging in temporally and potentially spatially segregated reproductive and non-breeding periods. Investigating behaviour and energy use across these periods is fundamental to understanding how animals survive the changing conditions associated with annual cycles. We estimated year-round activity budgets, energy expenditure, location, colony attendance and foraging behaviour for surviving individuals from a population of common guillemots Uria aalge. Despite the potential constraints of reduced day lengths and sea surface temperatures in winter, guillemots managed their energy expenditure throughout the year. Values were high prior to and during the breeding season, driven by a combination of high thermoregulatory costs, diving activity, colony attendance and associated flight. Guillemots also exhibited partial colony attendance outside the breeding season, likely supported by local resources. Additionally, there was a mismatch in the timing of peaks in dive effort and a peak in nocturnal foraging activity, indicating that guillemots adapted their foraging behaviour to the availability of prey rather than daylight. Our study identifies adaptations in foraging behaviour and flexibility in activity budgets as mechanisms that enable guillemots to manage their energy expenditure and survive the annual cycle

    Genomic organization and evolution of the ULBP genes in cattle

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    BACKGROUND: The cattle UL16-binding protein 1 (ULBP1) and ULBP2 genes encode members of the MHC Class I superfamily that have homology to the human ULBP genes. Human ULBP1 and ULBP2 interact with the NKG2D receptor to activate effector cells in the immune system. The human cytomegalovirus UL16 protein is known to disrupt the ULBP-NKG2D interaction, thereby subverting natural killer cell-mediated responses. Previous Southern blotting experiments identified evidence of increased ULBP copy number within the genomes of ruminant artiodactyls. On the basis of these observations we hypothesized that the cattle ULBPs evolved by duplication and sequence divergence to produce a sufficient number and diversity of ULBP molecules to deliver an immune activation signal in the presence of immunogenic peptides. Given the importance of the ULBPs in antiviral immunity in other species, our goal was to determine the copy number and genomic organization of the ULBP genes in the cattle genome. RESULTS: Sequencing of cattle bacterial artificial chromosome genomic inserts resulted in the identification of 30 cattle ULBP loci existing in two gene clusters. Evidence of extensive segmental duplication and approximately 14 Kbp of novel repetitive sequences were identified within the major cluster. Ten ULBPs are predicted to be expressed at the cell surface. Substitution analysis revealed 11 outwardly directed residues in the predicted extracellular domains that show evidence of positive Darwinian selection. These positively selected residues have only one residue that overlaps with those proposed to interact with NKG2D, thus suggesting the interaction with molecules other than NKG2D. CONCLUSION: The ULBP loci in the cattle genome apparently arose by gene duplication and subsequent sequence divergence. Substitution analysis of the ULBP proteins provided convincing evidence for positive selection on extracellular residues that may interact with peptide ligands. These results support our hypothesis that the cattle ULBPs evolved under adaptive diversifying selection to avoid interaction with a UL16-like molecule whilst preserving the NKG2D binding site. The large number of ULBPs in cattle, their extensive diversification, and the high prevalence of bovine herpesvirus infections make this gene family a compelling target for studies of antiviral immunity

    Aid to and from Family by Immigrants in College

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    This thesis examines various types of financial transfers between college students and their family members and how they differ by immigration status. Types of financial transfers examined include whether family members: helped students make tuition or loan payments, paid for unexpected expenses, provided health insurance, gave assistance with utilities and credit card payments, rent payments, or provided a regular allowance. Variables used to measure transfers from students to family members are whether students: babysat family member’s children or let family members live with them during college, and whether these services were done for free, and whether students gave money to family members while in college. Data was collected from a 2017 survey examining how over 3,000 college students pay for and experience college at The University of North Carolina at Greensboro and Rutgers University - Camden. Results were analyzed using mixed effects logistic regressions that controlled for gender, race, class, highest level of parent’s education, and for each university where data was collected. Results show immigrants are less likely to receive assistance with tuition or student loan payments, help with unexpected expenses, or be provided with health insurance by family members. Immigrants are less likely than non-immigrants to help their family members by babysitting for them, but twice as likely to help by letting them live with them during college. Immigrants not only let their family members live with them at a greater rate than non-immigrants, they also do so for free more often than non-immigrants. Lastly, immigrants babysit for their families less frequently than non-immigrants. Other results show immigrants and non-immigrants do not significantly differ in terms of aid received for utilities and credit card payments, rent, money given to family, receipt of allowance, or babysitting for free

    Generic local distinguishability and completely entangled subspaces

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    A subspace of a multipartite Hilbert space is completely entangled if it contains no product states. Such subspaces can be large with a known maximum size, S, approaching the full dimension of the system, D. We show that almost all subspaces with dimension less than or equal to S are completely entangled, and then use this fact to prove that n random pure quantum states are unambiguously locally distinguishable if and only if n does not exceed D-S. This condition holds for almost all sets of states of all multipartite systems, and reveals something surprising. The criterion is identical for separable and for nonseparable states: entanglement makes no difference.Comment: 12 page

    Digital Equity in the Time of COVID: Student Use of Technology for Equitable Outcomes

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    This issue brief is the third and final in a series published by the Metropolitan Educational Research Consortium (MERC) addressing digital equity in K-12 schools. It examines research regarding students’ use of and outcomes related to technology. Research finds that inequities exist in use and outcomes for students based on gender, language, ability, race, SES and other sociocultural factors. Based on these inequities, theoretical and practical recommendations are discussed

    Muscle Activity and User-Perceived Exertion During Immersive Virtual Reality Exergaming Incorporating an Adaptive Cable Resistance System

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    International Journal of Exercise Science 15(7): 261-275, 2022. The purpose of this exploratory study was to characterize muscle activation via surface electromyography (sEMG), user-perceived exertion, and enjoyment during a 30-minute session of immersive virtual reality (IVR) cable resistance exergaming. Ten healthy, college-aged males completed a signature 30-minute exergaming session using an IVR adaptive cable resistance system that incorporated six traditional compound exercises. Muscle activation (sEMG) was captured during the session with a wearable sEMG system. Rated of Perceived Exertion (RPE) and Physical Activity Enjoyment Scale (PACES) were recorded following the session. Pectoralis major showed the highest activation during chest press, deltoids showed the highest activation on overhead press, latissimus dorsi showed the highest activation during lat pulldown and row exercises, hamstrings were the most activated muscles during Romanian deadlift, and glutes showed the highest activity during squats. RPE and PACES mean scores were 14 (1) and 4.27 (0.38), respectively. IVR exergaming with resistance cable training provides an enjoyable experience and distracts practitioners from exertion while exercising at a high intensity. Results from this study suggest similar muscle activation responses compared to traditional resistance exercises as demonstrated with prior evidence. This novel form of exercise might have important repercussions for improving health outcomes among those who find it challenging to adhere to and enjoy exercise routines, as well as with little knowledge on how to progress in their resistance training. Further investigations are needed to explore long-term adaptations and to assess if IVR exergaming has additional benefits compared to traditional resistance training

    Long-range correlations in the mechanics of small DNA circles under topological stress revealed by multi-scale simulation

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    It is well established that gene regulation can be achieved through activator and repressor proteins that bind to DNA and switch particular genes on or off, and that complex metabolic networks deter- mine the levels of transcription of a given gene at a given time. Using three complementary computa- tional techniques to study the sequence-dependence of DNA denaturation within DNA minicircles, we have observed that whenever the ends of the DNA are con- strained, information can be transferred over long distances directly by the transmission of mechanical stress through the DNA itself, without any require- ment for external signalling factors. Our models com- bine atomistic molecular dynamics (MD) with coarse- grained simulations and statistical mechanical calcu- lations to span three distinct spatial resolutions and timescale regimes. While they give a consensus view of the non-locality of sequence-dependent denatura- tion in highly bent and supercoiled DNA loops, each also reveals a unique aspect of long-range informa- tional transfer that occurs as a result of restraining the DNA within the closed loop of the minicircles
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