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1.
Glob Chang Biol ; 30(6): e17340, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38840515

RESUMO

Grassy ecosystems cover more than 40% of the world's terrestrial surface, supporting crucial ecosystem services and unique biodiversity. These ecosystems have experienced major losses from conversion to agriculture with the remaining fragments threatened by global change. Woody plant encroachment, the increase in woody cover threatening grassy ecosystems, is a major global change symptom, shifting the composition, structure, and function of plant communities with concomitant effects on all biodiversity. To identify generalisable impacts of encroachment on biodiversity, we urgently need broad-scale studies on how species respond to woody cover change. Here, we make use of bird atlas, woody cover change data (between 2007 and 2016) and species traits, to assess: (1) population trends and woody cover responses using dynamic occupancy models; (2) how outcomes relate to habitat, diet and nesting traits; and (3) predictions of future occupancy trends, for 191 abundant, southern African bird species. We found that: (1) 63% (121) of species showed a decline in occupancy, with 18% (34) of species' declines correlated with increasing woody cover (i.e. losers). Only 2% (4) of species showed increasing population trends linked with increased woody cover (i.e. winners); (2) Open habitat specialist, invertivorous, ground nesting birds were the most frequent losers, however, we found no definitive evidence that the selected traits could predict outcomes; and (3) We predict open habitat loser species will take on average 52 years to experience 50% population declines with current rates of encroachment. Our results bring attention to concerning region-wide declining bird population trends and highlight woody plant encroachment as an important driver of bird population dynamics. Importantly, these findings should encourage improved management and restoration of our remaining grassy ecosystems. Furthermore, our findings show the importance of lands beyond protected areas for biodiversity, and the urgent need to mitigate the impacts of woody plant encroachment on bird biodiversity.


Assuntos
Biodiversidade , Aves , Ecossistema , Dinâmica Populacional , Animais , Aves/fisiologia , Conservação dos Recursos Naturais , África do Sul
2.
Integr Zool ; 14(1): 75-86, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30019856

RESUMO

Some rodents gather and store seeds. How many seeds they gather and how they treat those seeds is largely determined by seed traits such as mass, nutrient content, hardness of the seed coat, presence of secondary compounds, and germination schedule. Through their consumption and dispersal of seeds, rodents act as agents of natural selection on seed traits, and those traits influence how rodents forage. Many seeds that are scatter-hoarded by rodents are pilfered, or stolen, by other rodents, and seed traits also likely influence pilfering rates and seed fates of pilfered seeds. To clarify coevolutionary relationships between rodents and the plants that they disperse, one needs to understand the role of seed traits in rodent foraging decisions. We compared how the seeds of 4 species of plants that are dispersed by scatter-hoarding animals and that differ in value (singleleaf piñon pine, Pinus monophylla; desert peach, Prunus andersonii; antelope bitterbrush, Purshia tridentata; Utah juniper, Juniperus osteosperma) were pilfered and recached by rodents. One hundred artificial caches of the 4 seed species (25 per species) were prepared, and removal by rodents was monitored. Rodents pilfered high-value seeds more rapidly than the other seeds. Desert peach seeds, which contain toxic secondary compounds, were more frequently recached. Relatively low value seeds like Utah juniper and antelope bitterbrush were pilfered more slowly and were sometimes left at cache sites, and seeds of the latter species were transported shorter distances to new cache sites. The background density of seeds also appeared to influence the relative value of seeds.


Assuntos
Comportamento Alimentar/fisiologia , Roedores/fisiologia , Animais , Plantas/classificação , Sementes , Especificidade da Espécie
3.
Circulation ; 104(4): 399-405, 2001 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-11468200

RESUMO

BACKGROUND: Platelet deposition and aggregation are central to the pathogenesis of ischemic complications of acute coronary syndromes (ACS). Pharmacodynamic effects of the platelet glycoprotein IIb/IIIa antagonist eptifibatide have been delineated in healthy subjects but not in patients with ACS. We assessed effects of eptifibatide on ex vivo platelet aggregation in patients enrolled in the Platelet glycoprotein IIb/IIIa in Unstable angina: Receptor Suppression Using Integrilin (eptifibatide) Therapy (PURSUIT) trial of ACS. METHODS AND RESULTS: Patients were randomly assigned to an intravenous bolus (180 microgram/kg) and 72-hour infusion of eptifibatide (2.0 microgram/kg per minute, n=48) or placebo (n=50). We assessed correlations of plasma eptifibatide levels with receptor occupancy and inhibition of ex vivo platelet aggregation at 5 minutes and 1, 4, 24, 48, and 72 hours during treatment and 4 and 8 hours after termination of infusion. Blood was collected in buffered citrate and D-phenylalanyl-L-prolyl-L-arginine chloromethylketone anticoagulants. Although eptifibatide produced profound, prolonged inhibition of platelet aggregation during therapy, aggregation appeared to recover partially by 4 hours after the bolus. The aggregation response was greater with thrombin receptor agonist peptide versus ADP stimulation; inhibition of platelet aggregation was greater in blood samples anticoagulated with citrate versus D-phenylalanyl-L-prolyl-L-arginine chloromethylketone (PPACK). Plasma eptifibatide levels correlated significantly with receptor occupancy but not with inhibition of platelet aggregation. CONCLUSIONS: A bolus and infusion of eptifibatide inhibits platelet aggregation profoundly in patients with ACS and is followed by brief, partial recovery. These results enhance our understanding of the relation between pharmacodynamic and clinical effects of eptifibatide in such patients and may have important implications for its use in percutaneous interventions.


Assuntos
Angina Instável/tratamento farmacológico , Peptídeos/farmacocinética , Inibidores da Agregação Plaquetária/farmacocinética , Difosfato de Adenosina/farmacologia , Idoso , Clorometilcetonas de Aminoácidos/farmacologia , Angina Instável/sangue , Antitrombinas/farmacologia , Doença das Coronárias/sangue , Doença das Coronárias/tratamento farmacológico , Eptifibatida , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fragmentos de Peptídeos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/sangue , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Receptores de Trombina/efeitos dos fármacos , Receptores de Trombina/metabolismo , Fatores de Tempo
4.
Circulation ; 102(7): 728-35, 2000 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-10942739

RESUMO

BACKGROUND: Antiplatelet therapy is the mainstay of the treatment and secondary prevention of cardiovascular and cerebrovascular ischemic events. We assessed the safety, tolerability, and pharmacodynamics of lotrafiban, an oral platelet glycoprotein IIb/IIIa inhibitor, as a secondary prevention strategy in patients with cerebrovascular or cardiovascular disease. METHODS AND RESULTS: Overall, 451 patients with a recent cardiovascular or cerebrovascular acute ischemic event were randomized in a double-blind fashion to 1 of 5 dosing regimens for 12 weeks: placebo or 5, 20, 50, or 100 mg lotrafiban, both twice daily with 300 to 325 mg/d aspirin. The primary end point was the incidence and tolerability of major and minor bleeding during treatment. Secondary end points included inhibition of platelet aggregation and clinical events. The placebo and lotrafiban 5-mg groups had similarly low rates of minor and major bleeding, but the 100-mg arm was terminated early because of excess major bleeding. Protocol-defined thrombocytopenia (<100 000 platelets/microL) occurred in 5 lotrafiban-treated patients (1.4%, 95% CI 0.2% to 2.7%) and 1 placebo patient (1.1%, 95% CI 0% to 3.1%). Three lotrafiban-treated patients had a nadir platelet count <20 000/microL (0.9%, 95% CI 0% to 1.8%). Lotrafiban produced dose-dependent inhibition of platelet aggregation; 5 mg lotrafiban did not differ significantly from placebo, whereas 100 mg inhibited aggregation by nearly 100%. CONCLUSIONS: -Lotrafiban provides dose-dependent platelet inhibition when administered to a range of patients with atherosclerosis. The level of platelet inhibition appears to correlate with bleeding risk and drug tolerability.


Assuntos
Benzodiazepinas , Doença das Coronárias/tratamento farmacológico , Arteriosclerose Intracraniana/tratamento farmacológico , Piperidinas , Inibidores da Agregação Plaquetária/administração & dosagem , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Administração Oral , Idoso , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Hemorragia/induzido quimicamente , Humanos , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/efeitos adversos , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Trombocitopenia/induzido quimicamente , Resultado do Tratamento
5.
Nat Plants ; 1: 15141, 2015 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-27251393

RESUMO

The large brown, round, strongly scented seeds of Ceratocaryum argenteum (Restionaceae) emit many volatiles found to be present in herbivore dung. These seeds attract dung beetles that roll and bury them. As the seeds are hard and offer no reward to the dung beetles, this is a remarkable example of deception in plant seed dispersal.

6.
Cancer Epidemiol Biomarkers Prev ; 7(3): 195-8, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9521431

RESUMO

New diagnostic tools are needed to complement mammography and physical examinations for early detection of breast cancer, particularly among younger women. We evaluated the tumor biomarker, carcinoembryonic antigen (CEA), in 215 nipple aspirate fluid (NAF) samples collected from one or both breasts of 147 women, ages 27-87 years. Most subjects were recruited at the time of mammography examination. The 215 nipple fluid CEAs range from undetectable levels to 8400 ng/ml (median, 1100 ng/ml). Normal serum CEA levels are less than 6 ng/ml. There are no significant differences between the CEAs in fluid from normal breasts (112 samples) and breasts with various histories of tumors (total, 103 samples). Analyses for determinants of CEAs in fluids from normal breasts show higher levels among current smokers (P = 0.03) and marginal elevations among nulliparous women (P = 0.07). CEAs in these samples are not correlated with age, menopausal status, current hormone use, prior breastfeeding, or family history of breast cancer. Follow-up studies of these women and comparisons of CEAs in fluids from normal and cancer-containing breasts will help clarify whether this biomarker is useful for risk assessment or early cancer detection.


Assuntos
Neoplasias da Mama/prevenção & controle , Antígeno Carcinoembrionário/análise , Programas de Rastreamento , Mamilos/química , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/análise , Feminino , Humanos , Mamografia , Pessoa de Meia-Idade , Valores de Referência , Medição de Risco
7.
J Med Chem ; 40(16): 2466-73, 1997 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-9258353

RESUMO

Linear [6.6.6] tricyclic moieties whose center ring is made of two atoms of differing size (here primarily thioxanth-9-ones and phenoxathiins) monosubstituted meta to the sulfur by C(O)NHMe include potent and selective inhibitors of monoamine oxidase A. Similarities with effects on SAR of acylamide and of diazapentacyclic substitution on such rings, including positional variables, the requirement for monomethylation (primary and dialkylated amides are inactive and higher monoalkylated amides show little or no potency), and that sulfur is optimally in sulfone form, suggest that binding to the enzyme occurs similarly in each series. No significantly greater rise in blood pressure was found in rats given sufficient 8 to inhibit most brain and liver MAO A and then followed by oral tyramine than was found on administration of tyramine to controls. This is in contrast to a large blood pressure rise in rats pretreated with phenelzine followed by tyramine, and in accord with the belief that an inhibitor selective for MAO A which is reversibly bound to the enzyme and therefore displaced by any ingested tyramine will not lead to the "cheese effect" (hypertension during treatment with MAO inhibitors usually caused by ingestion of foods containing tyramine).


Assuntos
Antidepressivos Tricíclicos/síntese química , Ácidos Carboxílicos/química , Inibidores da Monoaminoxidase/síntese química , Animais , Antidepressivos Tricíclicos/farmacologia , Sítios de Ligação , Ácidos Carboxílicos/metabolismo , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Isoenzimas/metabolismo , Fígado/enzimologia , Masculino , Inibidores da Monoaminoxidase/farmacologia , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Especificidade por Substrato
8.
J Bone Joint Surg Am ; 66(7): 1040-8, 1984 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-6480633

RESUMO

We evaluated the results in eighty-three patients (ninety-five knees) who had had a high tibial osteotomy for either unicompartmental osteoarthritis or osteonecrosis. The operations were performed between 1965 and 1976. The mean length of follow-up was 8.9 years (range, five to fifteen years). The early results were promising: at two years 97 per cent and at five years 85 per cent of the knees had either an excellent or a good result. At subsequent follow-up, however, only sixty knees (63 per cent) had an excellent or good result, and in the remainder recurrent pain had developed. Twenty-two knees (23 per cent) had been revised to a total knee arthroplasty because of pain. The alignment obtained by the osteotomy was not as important in determining the long-term result as we had previously believed. Although recurrent varus deformity was observed in more than one-quarter of the knees, it was not necessarily associated with an unsatisfactory result. The passage of time was the most important factor in determining the result, as only fifteen (37 per cent) of the knees that had been followed for more than nine years were pain-free. We now believe that total knee arthroplasty is a more suitable operation for patients who are more than sixty years old and that high tibial osteotomy should be reserved for patients who have a strenuous occupation or who wish to continue to participate in sports activities.


Assuntos
Articulação do Joelho/cirurgia , Osteoartrite/cirurgia , Osteonecrose/cirurgia , Osteotomia , Tíbia/cirurgia , Adulto , Fatores Etários , Idoso , Feminino , Seguimentos , Humanos , Prótese do Joelho , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Fatores de Tempo
9.
J Bone Joint Surg Am ; 63(4): 560-9, 1981 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7217122

RESUMO

The anterior distal part of the iliotibial trace with attached bone block from Gerdy's tubercle was used as an intra-articular graft fixed by a screw to the tibia to control anterior instability (otherwise known as anterior, anteromedial, or anterolateral laxity) in twenty-four knees which were followed for two to four years. Concomitant single-plane 2+ to 4+ medial instability was present in eleven knees and was treated in five of them by simple immobilization, by imbrication of the medial collateral ligament, or by the Vigliani procedure. At follow-up, stability was improved and the result was rated good or excellent in twenty-one (88 per cent) of the twenty-four knees. The operation is applicable to the majority of chronic laxities of the knee and, because no immobilization is necessary, the postoperative care is much simplified and the rehabilitation time is much shorter. The procedure is contraindicated where there is posterior or single-plane lateral laxity.


Assuntos
Traumatismos do Joelho/cirurgia , Ligamentos Articulares/lesões , Adolescente , Adulto , Traumatismos em Atletas/cirurgia , Fascia Lata/cirurgia , Feminino , Humanos , Traumatismos do Joelho/diagnóstico , Articulação do Joelho/cirurgia , Ligamentos Articulares/cirurgia , Masculino , Métodos , Cuidados Pós-Operatórios , Complicações Pós-Operatórias , Tíbia/cirurgia
10.
Physician Exec ; 21(11): 26-30, 1995 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-10153732

RESUMO

An increasingly complex health care system undergoing rapid changes is an ideal set-up for frequent conflicts among the numerous participants. While conflict is inevitable, the manner in which it is handled can markedly affect the outcome of the dispute and the future relationship of the parties, as well as the emotional and financial cost of the dispute. This article presents an overview of the principles and processes of alternative dispute resolution (ADR), and describes how these processes are currently being used to resolve health care disputes.


Assuntos
Conflito Psicológico , Imperícia/legislação & jurisprudência , Negociação , Relações Médico-Paciente , Humanos , Estados Unidos
16.
Phys Chem Chem Phys ; 9(41): 5599-607, 2007 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-17957317

RESUMO

The absolute absorption cross section of IONO(2) was measured by the pulsed photolysis at 193 nm of a NO(2)/CF(3)I mixture, followed by time-resolved Fourier transform spectroscopy in the near-UV. The resulting cross section at a temperature of 296 K over the wavelength range from 240 to 370 nm is given by log(10)(sigma(IONO(2))/cm(2) molecule(-1)) = 170.4 - 3.773 lambda + 2.965 x 10(-2)lambda(2)- 1.139 x 10(-4)lambda(3) + 2.144 x 10(-7)lambda(4)- 1.587 x 10(-10)lambda(5), where lambda is in nm; the cross section, with 2sigma uncertainty, ranges from (6.5 +/- 1.9) x 10(-18) cm(2) at 240 nm to (5 +/- 3) x 10(-19) cm(2) at 350 nm, and is significantly lower than a previous measurement [J. C. Mössinger, D. M. Rowley and R. A. Cox, Atmos. Chem. Phys., 2002, 2, 227]. The photolysis quantum yields for IO and NO(3) production at 248 nm were measured using laser induced fluorescence of IO at 445 nm, and cavity ring-down spectroscopy of NO(3) at 662 nm, yielding phi(IO)

Assuntos
Algoritmos , Iodo/química , Nitratos/química , Ozônio/química , Espectrofotometria/métodos , Absorção/efeitos da radiação , Atmosfera/química , Iodo/efeitos da radiação , Modelos Químicos , Fotoquímica , Fotólise/efeitos da radiação , Teoria Quântica , Temperatura
17.
J Phys Chem A ; 110(1): 93-100, 2006 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-16392844

RESUMO

The kinetics of the reaction OIO+NO were studied by pulsed laser photolysis/time-resolved cavity ring-down spectroscopy, yielding k(235-320 K)=7.6(+4.0)(-3.1) x 10(-13) exp[(607+/-128)/T] cm3 molecule-1 s-1. Quantum calculations on the OIO+NO potential-energy surface show that the reactants form a weakly bound OIONO intermediate, which then dissociates to the products IO+NO2. Rice-Ramsberger-Kassel-Markus (RRKM) calculations on this surface are in good accord with the experimental result. The most stable potential product, IONO2, cannot form because of the significant rearrangement of OIONO that would be required. The reaction OIO+OH was then investigated by quantum calculations of the relevant stationary points on its potential-energy surface. The very stable HOIO2 molecule can form by direct recombination, but the bimolecular reaction channels to HO2+IO and HOI+O2 are closed because of significant energy barriers. RRKM calculations of the HOIO2 recombination rate coefficient yield krec,0=1.5x10(-27) (T/300 K)(-3.93) cm6 molecule-2 s-1, krec,infinity=5.5x10(-10) exp(46/T) cm3 molecule-1 s-1, and Fc=0.30. The rate coefficients of both reactions are fast enough around 290 K and 1 atm pressure for these reactions to play a potentially important role in the gas phase and aerosol chemistry in the marine boundary layer of the atmosphere.

18.
Med Group Manage J ; 42(4): 86-90, 92, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-10144247

RESUMO

Conflict is a growth industry, particularly in an increasingly complex health care system. Litigation is the most common, and most costly, method of settling health care disputes. Highly adversarial, the process of litigation often generates as much, if not more, hostility than the original dispute. In addition, satisfaction with the outcome is very low. The challenge that has arisen is to manage the conflicts so that the underlying needs and interests of all the parties can best be met. Often the techniques and processes of alternative dispute resolution (ADR) can be successfully used in resolving these sorts of conflicts quickly, cheaply and with greater satisfaction for all parties. Various applications of ADR are currently being used or tested in a variety of health care disputes in the United States and Canada. Tremendous success has been achieved in mediating medical malpractice claims, medical staff disputes, economic credentialing conflicts, insurer relations issues and denial of coverage disputes. Professional relations and departmental staff disputes, partnership and employee conflicts, and organizational disputes within clinics, HMOs and large group practices have all been found particularly amenable to ADR. These are all situations in which everyone benefits from quick, non-hostile resolutions and on-going relationships can continue.


Assuntos
Conflito Psicológico , Prática de Grupo/legislação & jurisprudência , Responsabilidade Legal/economia , Negociação , Canadá , Controle de Custos/métodos , Credenciamento/legislação & jurisprudência , Ética Médica , Prática de Grupo/economia , Imperícia/legislação & jurisprudência , Estados Unidos
19.
Phys Rev Lett ; 86(11): 2249-52, 2001 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-11289901

RESUMO

The rotational angular momentum orientation and alignment of the NO fragments generated via linearly polarized 308 nm photodissociation of NO2 has been determined using laser induced fluorescence. By observing the dependence of the photofragment NO Doppler-resolved transition line shapes on experimental geometry, it has proved possible to determine multipole moments of the photofragment angular momentum distribution up to, and including, rank 3. The implications of the results for the mechanism of the dissociation are considered.

20.
Indian J Psychiatry ; 29(4): 325-31, 1987 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21927263

RESUMO

Life table method was presented as a method of choice to analyse data arising out of longitudinal studies. The method was employed to study length of stay (LOS) of psychiatric in-patients. The result obtained was compared with LOS calculated by traditional methods. The LOS was 58-60 days computed by traditional methods for the year 1985 for our centre. This was shown by the life table method as the expected LOS at the time of admission. The life table method demonstrated that the rate of discharge increased as the length of stay increased upto 30 days and decreased afterwards. On the other hand, the expected further LOS increased as the length of stay increased upto 3 years. The implications of the findings were discussed.

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