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H P Schmid

Publications and source records attributed to H P Schmid.

At least 19 recordsLinked to original sources
PubMed2005

Predicting the onset of net carbon uptake by deciduous forests with soil temperature and climate data: a synthesis of FLUXNET data.

We tested the hypothesis that the date of the onset of net carbon uptake by temperate deciduous forest canopies corresponds with the time when the mean daily soil temperature equals the mean annual air temperature. The hypothesis was tested using over 30 site-years of data from 12 field sites where CO(2) exchange is being measured continuously with the eddy covariance method. The sites spanned the geographic range of Europe, North America and Asia and spanned a climate space of 16 degrees C in mean annual temperature. The tested phenology rule was robust and worked well over a 75 day range of the initiation of carbon uptake, starting as early as day 88 near Ione, California to as late as day 147 near Takayama, Japan. Overall, we observed that 64% of variance in the timing when net carbon uptake started was explained by the date when soil temperature matched the mean annual air temperature. We also observed a strong correlation between mean annual air temperature and the day that a deciduous forest starts to be a carbon sink. Consequently we are able to provide a simple phenological rule that can be implemented in regional carbon balance models and be assessed with soil and temperature outputs produced by climate and weather models.

Air↗
PubMed2005

Environmental controls on sap flow in a northern hardwood forest.

Our objective was to gain a detailed understanding of how photosynthetically active radiation (PAR), vapor pressure deficit (D) and soil water interact to control transpiration in the dominant canopy species of a mixed hardwood forest in northern Lower Michigan. An improved understanding of how these environmental factors affect whole-tree water use in unmanaged ecosystems is necessary in assessing the consequences of climate change on the terrestrial water cycle. We used continuously heated sap flow sensors to measure transpiration in mature trees of four species during two successive drought events. The measurements were scaled to the stand level for comparison with eddy covariance estimates of ecosystem water flux (Fw). Photosynthetically active radiation and D together explained 82% of the daytime hourly variation in plot-level transpiration, and low soil water content generally resulted in increased stomatal sensitivity to increasing D. There were also species-specific responses to drought. Quercus rubra L. showed low water use during both dry and wet conditions, and during periods of high D. Among the study species, Acer rubrum L. showed the greatest degree of stomatal closure in response to low soil water availability. Moderate increases in stomatal sensitivity to D during dry periods were observed in Populus grandidentata Michx. and Betula papyrifera Marsh. Sap flow scaled to the plot level and Fw demonstrated similar temporal patterns of water loss suggesting that the mechanisms controlling sap flow of an individual tree also control ecosystem evapotranspiration. However, the absolute magnitude of scaled sap flow estimates was consistently lower than Fw. We conclude that species-specific responses to PAR, D and soil water content are key elements to understanding current and future water fluxes in this ecosystem.

Acer↗
PubMed2005

Respiratory carbon losses and the carbon-use efficiency of a northern hardwood forest, 1999-2003.

Quantitative assessment of carbon (C) storage by forests requires an understanding of climatic controls over respiratory C loss. Ecosystem respiration can be estimated biometrically as the sum (R Sigma) of soil (Rs), leaf (Rl) and wood (Rw) respiration, and meteorologically by measuring above-canopy nocturnal CO2 fluxes (Fcn). Here we estimated R Sigma over 5 yr in a forest in Michigan, USA, and compared R Sigma and Fcn on turbulent nights. We also evaluated forest carbon-use efficiency (Ec = P(NP)/P(GP)) using biometric estimates of net primary production (P(NP)) and R Sigma and Fcn-derived estimates of gross primary production (P(GP)). Interannual variation in R Sigma was modest (142 g C m(-2) yr(-1)). Mean annual R Sigma was 1425 g C m(-2) yr(-1); 71% from Rs, 18% from Rl, and 11% from Rw. Hourly R Sigma was well correlated with Fcn, but 11 to 58% greater depending on the time of year. Greater R Sigma compared with Fcn resulted in higher estimated annual P(GP) and lower annual Ec (0.42 vs 0.54) using biometric and meteorological data, respectively. Our results provide one of the first multiyear estimates of R Sigma in a forested ecosystem, and document the responses of component respiratory C losses to major climatic drivers. They also provide the first assessment of Ec in a deciduous forest using independent estimates of P(GP).

Carbon↗
PubMed2003

[Testicular tumors--a current review].

Only 1% of all male tumors are testicular origin, but it is the most frequent neoplasia in younger men. Risk factors include cryptorchism and a positive personal history of testicular cancer. Testicular cancer is divided in germ cell cancer and non germ cell cancer, the latter accounting for about 5%. Germ cell cancer is classified in seminoma and nonseminoma. Usually the first clinical presentation is painless swelling. Afterwards ultrasonography is indicated and tumor markers should be analysed. The first therapeutic step is always a radical inguinal orchiectomy. The following treatment depends on the staging: wait and see, radiotherapy or chemotherapy. Testicular cancer is characterised by a good cure rate (98-100% early stages) or recurrence free survival (80-90% late stages).

Adult↗
PubMed2003

[Bladder carcinoma--a current review].

Bladder cancer is the sixth most common malignant tumor. The course of the disease depends largely on histological findings. A combination of transurethral resection and intravesical chemotherapy is indicated in superficial tumors and is able to cure most patients with a well differentiated cancer. Contrary to that, muscle-invasive and poorly differentiated tumors take a much less favorable course. They can be offered novel combined therapeutic approaches or/and at least orthotopic continent bladder substitution. It seems possible that the recently observed trend towards improved overall survival may continue. In the future, there should be more emphasis on prevention (elimination of carcinogens and early detection).

Chemotherapy, Adjuvant↗
PubMed2001

EAU guidelines on prostate cancer.

OBJECTIVES: To develop clinical guidelines for the management of patients with prostate cancer. METHODS: Guidelines were compiled by a working panel based on current literature following a literature review using MEDLINE. Already published structured analysis from national and international guidelines was used, and panel consensus was employed when literature evidence was absent or of poor quality. RESULTS: The full text of the guidelines is available through the EAU Central Office and the EAU website (www.uroweb.org). This article summarizes the main conclusions from the guidelines concerning the diagnosis and staging, treatment and follow-up of patients with prostate cancer. The diagnosis of prostate cancer should be based on histopathological or cytological examinations. N- and M-staging may be omitted in selected patients with a low serum prostate-specific antigen due to low risk of metastasis. Active treatment is warranted in most stages of prostate cancer but active monitoring is recommended for elderly patients with early stage tumours and is still optional in some other situations. Follow-up is based on a disease-specific history, serum-prostate-specific antigen supplemented by a digital rectal examination. Routine imaging is not necessary in asymptomatic patients. CONCLUSIONS: Prostate cancer is one of the most common malignancies in men. These guidelines have been drawn up to provide support in the management of this large group of patients.

Follow-Up Studies↗
PubMed2001

Active monitoring (deferred treatment or watchful waiting) in the treatment of prostate cancer. A review.

OBJECTIVES: To evaluate the concept of active monitoring only in the management of patients with prostate cancer. METHODS: Literature review. RESULTS: Active monitoring may be recommended in patients with stage T1a, well- and moderately-differentiated disease. Patients with a life expectancy exceeding 10 years are recommended re-evaluation with PSA, TRUS and biopsies of the residual prostate. This treatment is also indicated in patients with stage T1b-T2b, well- and moderately-differentiated tumours and a life expectancy of less than 10 years. Active monitoring is optional in patients with stage T1b-T2b, Gleason 2-4 prostate cancer and a life expectancy of 10-15 years. It is also optional in asymptomatic patients with locally advanced disease, stage T3-T4 which are well- and moderately-differentiated and have a short life expectancy. A very rare asymptomatic patient with M1 disease and the possibility of close follow-up may be offered active monitoring. CONCLUSIONS: Active monitoring is still a viable option for selected patients diagnosed with prostate cancer.

Adenocarcinoma↗
PubMed2001

Predictive value of radiological criteria for disintegration rates of extracorporeal shock wave lithotripsy.

OBJECTIVE: To evaluate routinely applicable criteria to predict fragmentation of renal calculi by extracorporeal shock wave lithotripsy (ESWL). PATIENTS AND METHODS: Two hundred and two consecutive patients (121 men, 81 women), median age 48 (range 19-81) years, were treated with the original Dornier HM-3 lithotriptor at a single stone center. Inclusion criteria were: solitary stones, 10-30 mm in greatest diameter, located in renal pelvis or calyces. Based on plain radiographs, the calculi were classified according to their size, form, location, density (compared to the 12th rib), structure and surface. Furthermore, age of the patient, gender and body mass index were also considered for evaluation. Disintegration was documented on day 1 after ESWL by plain X-ray. A multivariate regression analysis was applied to all preoperative parameters, based on the dual variable stone free versus residual fragments. RESULTS: The overall disintegration rate was 95.5%; 42 patients (20.8%) were completely stone free, and 151 patients (74.7%) had clinically insignificant residual fragments (5 mm or smaller). 14.9% of men and 29.6% of women were stone free (p = 0.01). All other parameters did not reach statistical significance. CONCLUSIONS: The disintegration rate of the HM-3 is excellent for kidney stones; women did significantly better than men. However, because of this high disintegration rate, a much larger series would be necessary to define possible differences between preinterventional parameters, if there were any at all.

Adult↗
PubMed2001

Comparison of carotid arterial resistive indices with intima-media thickness as sonographic markers of atherosclerosis.

UNLABELLED: Background and Purpose-The intima-media thickness (IMT) of the carotid artery is a (morphological) sonographic parameter that depends on the degree of atherosclerosis. In the renal arteries, the value of the (hemodynamic) resistive index (RI) is correlated with the severity of atherosclerosis. In contrast to the well-known IMT, no study has yet applied the carotid RI to estimate generalized atherosclerosis. METHODS: -The SMART atherosclerosis risk score was determined in 157 patients (94 men and 63 women; mean age 63 [range 19 to 80] years) with at least 1 vascular risk factor or a known vascular disease. Duplex sonography of the common carotid (CCA) and internal carotid artery (ICA) was then performed, with determination of IMT and RI. RESULTS: -The mean risk score of all patients was 8.8+/-3.5 (range 1 to 17), the mean IMT value in the CCA was 0.727+/-0.161 mm, the mean RI in CCA was 0.79+/-0.066, and the mean RI in ICA was 0.661+/-0.082. Highly significant correlations were found between the score and IMT CCA and the score and RI ICA (r=0.62, P:<0.0001 and r=0.55, P:<0.0001). The score-RI CCA correlation was much less marked (r=0.354, P:<0.0001). The intraobserver and interobserver agreement was less for IMT than for RI CCA and ICA. The areas under the curve of the receiver operating curves to distinguish between low-risk and high-risk patients resulted in values of 0.86, 0.81, and 0.69 for IMT, RI ICA, and RI CCA, respectively. CONCLUSIONS: -Although RI reflects the atherosclerotic process in an indirect manner, the correlation between the RI ICA and the SMART atherosclerosis score as well as the ability to distinguish between low- and high-risk patients are comparable to those of the well-known IMT.

Adult↗
PubMed2000

Five meters of H(2)O: the pressure at the urinary bladder neck during human ejaculation.

BACKGROUND: There are no data in the literature on pressure changes in the prostatic urethra during ejaculation. In healthy men, it has always been postulated that there must be a pressure gradient in order to prevent retrograde ejaculation, but scientific proof for that is pending. METHODS: In five healthy male volunteers, the pressure profile in the prostatic urethra was registered during ejaculation, using a 10 French balloon catheter with 16 pressure channels. The channels were arranged in pairs at 5-mm intervals, beginning just below the balloon at the bladder neck and extending down to the external urethral sphincter. RESULTS: In the proximal part of the prostatic urethra, a pressure of up to 500 cm of H(2)O was measured in all subjects. Contrary to that, pressures did not exceed 400 cm of H(2)O distally to the verumontanum. CONCLUSIONS: A novel method to register the pressure profile in the lower urinary tract during ejaculation (ejaculomanometry) is presented. This study adds to the knowledge of the normal physiology of reproductive function and may be useful in the evaluation of male sexual and reproductive disorders.

Adult↗
PubMed2000

[Paratesticular sarcomas. Case report of leiomyosarcoma].

Paratesticular sarcomas are rare. We discuss this entity with the aid of a case report and the existing literature. The therapy of these tumors includes resection and possible adjuvant radiotherapy. Rhabdomyosarcomas are an exception, because they also show a good response to chemotherapy.

Diagnosis, Differential↗
PubMed2000

[Value of hydrodistention and bladder training].

Although hydrodistension of the bladder is generally considered standard therapy for interstitial cystitis, scientific data are largely lacking. With the mechanism of action unknown, prospective studies non-existent and the therapeutic effect at best very short-lived, hydrodistension cannot be regarded as a therapeutic standard concept with scientifically validated efficacy. The value of behavioral therapy and bladder training is equally unclear; success can only be anticipated in the very rare subset of patients without pain.

Cystitis, Interstitial↗