522 research outputs found
A comparison of CDMA techniques for third generation mobile radio systems
A comparison is made between both direct sequence (DS) and frequency hopping (FH) spreading techniques in code division multiple access (CDMA) based upon the stringent requirements of proposed third generation mobile radio systems in Europe. Given the many criteria against which this comparison is made, the outcome is slightly in favour of DS-CDMA
Search for Gravitational Waves from Primordial Black Hole Binary Coalescences in the Galactic Halo
We use data from the second science run of the LIGO gravitational-wave
detectors to search for the gravitational waves from primordial black hole
(PBH) binary coalescence with component masses in the range 0.2--.
The analysis requires a signal to be found in the data from both LIGO
observatories, according to a set of coincidence criteria. No inspiral signals
were found. Assuming a spherical halo with core radius 5 kpc extending to 50
kpc containing non-spinning black holes with masses in the range 0.2--, we place an observational upper limit on the rate of PBH coalescence
of 63 per year per Milky Way halo (MWH) with 90% confidence.Comment: 7 pages, 4 figures, to be submitted to Phys. Rev.
Comparative analysis of RNA sequencing methods for degraded or low-input samples
available in PMC 2014 January 01RNA-seq is an effective method for studying the transcriptome, but it can be difficult to apply to scarce or degraded RNA from fixed clinical samples, rare cell populations or cadavers. Recent studies have proposed several methods for RNA-seq of low-quality and/or low-quantity samples, but the relative merits of these methods have not been systematically analyzed. Here we compare five such methods using metrics relevant to transcriptome annotation, transcript discovery and gene expression. Using a single human RNA sample, we constructed and sequenced ten libraries with these methods and compared them against two control libraries. We found that the RNase H method performed best for chemically fragmented, low-quality RNA, and we confirmed this through analysis of actual degraded samples. RNase H can even effectively replace oligo(dT)-based methods for standard RNA-seq. SMART and NuGEN had distinct strengths for measuring low-quantity RNA. Our analysis allows biologists to select the most suitable methods and provides a benchmark for future method development.National Institutes of Health (U.S.) (Pioneer Award DP1-OD003958-01)National Human Genome Research Institute (U.S.) (NHGRI) 1P01HG005062-01)National Human Genome Research Institute (U.S.) (NHGRI Center of Excellence in Genome Science Award 1P50HG006193-01)Howard Hughes Medical Institute (Investigator)Merkin Family Foundation for Stem Cell ResearchBroad Institute of MIT and Harvard (Klarman Cell Observatory)National Human Genome Research Institute (U.S.) (NHGRI grant HG03067)Fonds voor Wetenschappelijk Onderzoek--Vlaandere
Arbuscular mycorrhizal colonisation of roots of grass species differing in invasiveness
Recent research indicates that the soil microbial community, particularly arbuscular mycorrhizal
fungi (AMF), can influence plant invasion in several ways. We tested if 1) invasive species are
colonised by AMF to a lower degree than resident native species, and 2) AMF colonisation of native
plants is lower in a community inhabited by an invasive species than in an uninvaded resident
community. The two tests were run in semiarid temperate grasslands on grass (Poaceae) species,
and the frequency and intensity of mycorrhizal colonisation, and the proportion of arbuscules and
vesicles in plant roots have been measured. In the first test, grasses representing three classes of
invasiveness were included: invasive species, resident species becoming abundant upon
disturbance, and non-invasive native species. Each class contained one C3 and one C4 species. The
AMF colonisation of the invasive Calamagrostis epigejos and Cynodon dactylon was consistently
lower than that of the non-invasive native Chrysopogon gryllus and Bromus inermis, and contained
fewer arbuscules than the post-disturbance dominant resident grasses Bothriochloa ischaemum and
Brachypodium pinnatum. The C3 and C4 grasses behaved alike despite their displaced phenologies
in these habitats. The second test compared AMF colonisation for sand grassland dominant grasses
Festuca vaginata and Stipa borysthenica in stands invaded by either C. epigejos or C. dactylon, and
in the uninvaded natural community. Resident grasses showed lower degree of AMF colonisation in the invaded stand compared to the uninvaded natural community with F. vaginata responding so to
both invaders, while S. borysthenica responding to C. dactylon only. These results indicate that
invasive grasses supposedly less reliant on AMF symbionts have the capacity of altering the soil
mycorrhizal community in such a way that resident native species can establish a considerably
reduced extent of the beneficial AMF associations, hence their growth, reproduction and ultimately
abundance may decline. Accumulating evidence suggests that such indirect influences of invasive
alien plants on resident native species mediated by AMF or other members of the soil biota is probably more the rule than the exception
Chemical diversity in a metal-organic framework revealed by fluorescence lifetime imaging
The presence and variation of chemical functionality and defects in crystalline materials, such as metal–organic frameworks (MOFs), have tremendous impact on their properties. Finding a means of identifying and characterizing this chemical diversity is an important ongoing challenge. This task is complicated by the characteristic problem of bulk measurements only giving a statistical average over an entire sample, leaving uncharacterized any diversity that might exist between crystallites or even within individual crystals. Here we show that by using fluorescence imaging and lifetime analysis, both the spatial arrangement of functionalities and the level of defects within a multivariable MOF crystal can be determined for the bulk as well as for the individual constituent crystals. We apply these methods to UiO-67, to study the incorporation of functional groups and their consequences on the structural features.
We believe that the potential of the techniques presented here in uncovering chemical diversity in what is generally assumed to be homogeneous systems can provide a new level of understanding of materials properties
Dyadic adjustment, family coping, body image, quality of life and psychological morbidity in patients with psoriasis and their partners
Background Psoriasis is an incurable and chronic disease
that includes unpredictable periods of remission and relapse
requiring long-term therapy.
Purpose This paper focuses on the relationship among
family coping, psychological morbidity, body image,
dyadic adjustment and quality of life in psoriatic patients
and their partners.
Method One hundred and one patients with psoriasis and
78 partners comprised the sample. They were regular users
of the Dermatology Service of a Central Northern hospital
in Portugal and a private dermatology clinic. Patients with
psoriasis were assessed on anxiety, depression, body image,
quality of life, dyadic adjustment and family coping.
Partners were assessed on the same measures except body
image and quality of life.
Results A positive relationship among dyadic adjustment,
psychological morbidity and family coping in patients and
their partners was found. Also, patients with lower levels of
quality of life had partners with higher levels of depressive
and anxious symptoms. Better dyadic adjustment predicted
family coping in the psoriatic patient. High levels of dyadic
adjustment in patients and low partners’ trait anxiety
predicted better dyadic adjustment in partners.
Conclusion The results highlight the importance of incorporating
family variables in psychological interventions in
psoriasis’ care, particularly family coping and dyadic
adjustment as well as the need for psychological intervention
to focus both on patients and partners
A study of a couple with type 2 diabetes: dyadic adjustment and psychological morbidity
Objective: this study assessed dyadic adjustment and psychological morbidity
in type 2 diabetic patients and their partners, focusing on the role of gender.
Methods: 214 diabetic patients and their partners participated in the cross-sectional
study and were assessed on psychological morbidity (HADS) and marital
adjustment (RDAS). Data was analyzed using dyadic analysis, a statistical process
that studies the patient/partner dyads simultaneously.
Results: results revealed that the negative relationship between dyadic adjustment
and psychological morbidity in female patients was stronger than in male
diabetic patients or in partners of male diabetic patients. On the other hand, the
relationship between dyadic adjustment and psychological morbidity in partners
of diabetic men was stronger than the same relationship in partners of diabetic
women.
Conclusion: since gender is a moderator, it is important to attend to the different
needs of female and male patients and the education of diabetic patients
should be centered on the patient/partner dyad.Fundação para a Ciência e a Tecnologia (FCT
The application of frequency hopping CDMA for future universal Personal Communications Systems
The UK LINK personal communications programme : downlink synchronisation for a DS-CDMA field trial system
Expanding the diversity of mycobacteriophages: Insights into genome architecture and evolution
Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists. © 2011 Hatfull et al
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